Whenever I revisit comics and SF from the 40’s to 60’s or so (and even quite a bit beyond) I realize that the adults of the time who were critisizing it as brain-rotting crap were mostly right. The majority of that stuff was incredibly awful.
I don’t know… I remember being if not a closeted nerd, at least somewhat circumspect about what I was reading, or what I did in my spare time (played computer games on my c64, played RPGs, painted miniatures, etc…)
Maybe it’s nerd culture that was unacceptable, not sci-fi/fantasy specifically. I’m still routinely amazed at the pervasiveness of nerd culture in Gen-Z and even younger millenials’ lives- so much of that stuff would have been unspeakably nerdy in say… 1992.
I’m older - 62. Nerd genre was not the mainstream cash cow that it has become but I was 18 to 19 the years Star Wars and Superman came out. Big budget films that brought in both huge amounts in the box office and in associated goodies. Close Encounters same year as Star Wars and the first Star Trek movie in that same time period. There was not a lot of mocking or scorn of adults who saw these movies. Of the Star Trek movie yeah … Logan’s Run '76, Soylent Green and Westworld '73. Adults saw these movies without suffering scorn. The big hits of their years no.
1968 had both 2001 A Space Odyssey and Planet of the Apes. Fahrenheit 451 was is 1966. Those older than me will have to attest to whether or not adults were mocked for going to see any of them.
Mind you adults reading comic books was not so cool …
Yeah, I think all that “nerd” stuff was kind of “cool” or accepted on some level when I was a kid. But once I got to around middle school age, most people I knew more or less grew out of it.
Not everyone is hating because it’s trendy. Or to hang with the cool hater kids. At lot of us come by our “hate” for a movie naturally.
Oh there are plenty of reasons.
Well, haters gonna hate. 
Yes, yes, yes, yes, yes, yes.
But the 60s were different. Stan Lee transformed Marvel so that by the end of the 60s it was a cult product on college campuses. A new group of actually literate writers started appearing in science fiction in the mid-60s, and they wrote thoroughly respectable fiction. LotR was published in paperback in the 60s and set off a fantasy boom for the works of English dons. 2001 was made for the LSD generation, and it raised expectations (although really it was one of a kind and those expectations weren’t met).
You can’t compare attitudes toward nerd culture in the 70s and 80s to earlier decades anymore than you can compare attitudes toward rock then to the pre-Beatles era. The world turned upside down.
I agree with pretty much everyone in the thread mentioning that the loudest voices belonging to the extremes drown out everyone else when it comes to reviews and judgements. No one gets any attention or sparks debate by simply stating they enjoyed a movie or show for light entertainment and nothing more.
I would also agree with the suggestion that there may be an over-saturation these days which makes it harder for shows of a particular genre to be unique or to appear worth the while. Certainly questioning whether it was worth the expense.