Hilariously (or at least it is to me, sitting here munching popcorn), the answer given is… a non-answer.
Like most disasters this one had a large number of contributing causes - originally, there were two other bids for the 2023 Worldcon: a group in Memphis and a group in Nice (France). Either one of those might very well have won, but both of them had problems and withdrew. At the last minute (or maybe afterwards) a new bid was made (by a group from Winnipeg), but my impression is that it wasn’t a very well-run bid, and didn’t have much going on for it other than being a non-Chengdu bid. A few well-known-fans worked with the Chinese bidders and vouched for the bidders’ enthusiasm and preparedness, and the large number of votes from Chinese fans (or fake Chinese fans - I’m agnostic on that issue) won the day, but Memphis or Nice might very well have won instead. Fans do like to travel to Worldcons (Australia and Japan and NZ and Scotland and Helsinki), so some non-Chinese fans accepted the assurances that all was well.
Then the screw-ups became obvious - Hugo nominating was delayed, the venue was changed, the dates were changed, etc. All this smacks of over-ambition, and of desperation leading to selling out to the industry groups that could fund the huge new facility - and rather than throwing up a flare, the non-Chinese participants in the committee went along. Even now, it’s not clear that the Chinese government needed to do anything - it’s so screwed up that the Hugo admin may be implying pressure on him to cover up the fact that he discovered that he’d got the nomination results badly wrong (the finalists were announced - late - then retracted and corrected). I think Babel is actually available in China, which makes its exclusion weird. As Asimov said, to understand history you shouldn’t worry about who’s outsmarting whom - worry about who’s outstupiding whom
PS - now if you want one author to be disappointed in - it’s Robert Sawyer. Accepted the position of Guest of Honor along with propagandists for the Ukrainian invasion and the Uigyr oppression, and stuck through to the end
TPTB must not have read his WWW trilogy, where the Internet becomes sentient and benevolent and at one point basically tells the Chinese government “Hi, you’re a democracy now…or else”.
Hmm. Here’s what he said at the con “It’s said of China that you live in a peaceful country in a world that is not at peace. Here, people from all over the world unite, believing there will be a future. This World Science Fiction Convention sends a positive message to the world.”
Yes, I know, I went to several. But they went to China.
Because they live in a nation with limited freedoms, and no free speech?
Which apparently fixed the election?
True, but it is relevant to my enjoyment as a reader.
I did some digging (I haven’t read the books since they were first released) and the climax of the action takes place in chapters 39 and 40 of the 3rd book in the trilogy.
The Internet (named “Webmind”) had been working alongside a team of underground Chinese hackers, which had forgotten. In this scene, some of them have gathered in Tiananmen Square when every cell phone in China gets a text message…
The square was noisy, as always: the chatter of countless people, the snapping of flags, the cooing of pigeons. But it was suddenly filled with even more sound.
Sinanthropus’s phone came to life. His ringtone was “Do You Hear the People Sing?” from Les Miserables; when he’d been eighteen, he’d seen the subtitled live production in Shanghai starring Colm Wilkinson.
Near him, another phone woke up; its ringtone was “Liu Xia Lai” by Fahrenheit.
In front of him another played Wu Qixian’s “I Believe the Future.”
Behind him, a fourth rang out with the drumbeats of “March of the Volunteers,” China’s national anthem.
And then, so many more, so many thousands and thousands more. To Sinanthropus’s surprise, it was not a cacophony but a vast glorious symphony of sound, emanating from all around him—from every part of the square, and, he knew, from every corner of the land: from the high places and the low, from cities and villages, from the Great Wall and countless rice paddies, from skyscrapers and temples and houses and huts.
People looked at each other in astonishment. And then, all too soon, the wondrous sound began to abate as fingers were swiped across iPhones, cells were snapped open, BlackBerrys were brought to life.
Sinanthropus looked down at the small screen on his own phone, checking to see which of the two messages Webmind had sent.To the glorious people of China:
Effective immediately, we, the leaders of your government, have voluntarily stepped down. It has long been our dream to form the perfect nation here, and now that dream is reality. Henceforth all of you—the billion-plus citizens of this proud land—will collectively decide your fate.
More details may be found at this website.
It has been my privilege to lead you. And now, to the wonderful future!
The Internet addresses a meeting of the Chinese leadership (who definitely did not authorize that text). Shows them photos that include ones from the Tiananmen Square massacre, tells them what the new reality is going to be, and concludes with:
“Over the next half hour, in four waves, I am going to send an SMS message to every cell phone in China announcing the transition; for those in the first wave who are on the China Mobile network, I will trigger the phones to ring so that the message will be given immediate attention.”
The large window showing Tank Man was replaced with two documents, while the procession of faces continued in the small window. The document on the left was a short announcement signed by the former president describing the voluntary dissolution of his government and the transfer of power to the people. On the right was a similar message from Webmind that made no mention of the previous government having cooperated in the change.
“Take your pick,” Webmind said.
(The implied threat being that either they play along and say they volunteered to step down, or they be removed less plesantly.)
So we can rest assured that the top party officials are not familiar with the writings of Robert J Sawyer.
I’m sure that is said of China.
This sounds like the official US policy with regard to Taiwan that there is One China (but refraining from specifying which one).
I now see the guests of honor are Cixin Liu, which is not a surprise but not without CCP controversy. But also Sergei Lukyanenko who definitely has some more universally politically unpalatable views including a lot of cheerleading for invading Ukraine. What a mess.
Jeez. What would you invite that guy as a Guest of Honor? I mean it’s like inviting Goebbels. The Hugos have lost now all my respect.
Sergei was an unexplained no-show, the Con never admitted that he wasn’t there…and a couple of weeks after the convention ended he was given a tour of the con facilities and was treated like royalty.
Looks like the Chinese fans are none too happy about what went down, either.
“I’m just saying, lots of people say that.” 
Note that the next two Worldcons will be in Glasgow and Seattle and will what I think are pretty unobjectionable guests of honor:
I don’t find anything objectionable about recent Hugos for best novels either:
I know that the supposed reason for the Chengdu WorldCon committee excluding these works from the ballot has not been stated (admitted?). But has any work in the history of the Hugos ever been excluded from the ballot for any reason other than for not meeting the stated requirements for the category for which they were nominated?
I don’t think so, though I think there have been some cases where there’s been debate in some cases where a mistake in the requirements check may have been made or where the qualification rules have needed subsequent clarification for previously untested edge cases.
That said, there’s a new person in charge of the awards administration this year, as alluded above, and simple incompetence is also entirely plausible.
Also, the Hugos have been notoriously loose in their standards of what kinds of works are eligible. The TV footage of the first Moon landing was counted as a “dramatic presentation”, and I can’t even remember what category they shoehorned Randall Munroe’s “Time” into (looking it up, it was “Best Graphic Story”). Basically, if the fans want to honor something, they’ll figure out some way to.
And apparently some of the administrators have figured out the obverse to that….
As a side note, since the 2024 Worldcon will be held in Glasgow, there will be a North American SF Convention (NASFiC) in Buffalo, NY, with Alan Dean Foster as the author GoH.
Two controversial exclusions (though not as bad as this): Mary Robinette Kowal’s story “The Lady Astronaut of Mars” was excluded for best novelette because it was first published as an audio piece, and the Silmarillon was excluded as best novel because the administrator considered it to be a collection of shorter pieces with a novel and the foolish voters hadn’t thought of nominating the novel part