The guy got in trouble because he claimed that a trans woman was almost certainly faking being a trans woman. He was specifically ignoring how she identified. That’s the rule he broke.
If I say that some black guy is faking being black, that’s obviously an insult. If I say they’re faking being gay, that’s an insult.
You don’t need any of the convoluted rules the guy is going on about to understand what the problem was. Don’t accuse a trans person of faking it. And call them what they want to be called.
There’s a reason the thread you posted pretty much immediately ignored the guy and moved on.