I think a lot of people were in a lot of training sessions being told about how hard it is to be trans/queer etc. They fundamentally want people to be happy so they go along with the premise because that’s what people want and people will be happier.
“I’m a nice guy, look, I pay attention in training and I’m proud to be an ally!”.
They get emails complaining, and hear the shrill whispers of bigoted women (faintly, in the distance) and ignore them because 1. Women, 2. Shrill, 3. Their own work is important and busy and they mustn’t be interrupted by those shrill whispering bigots in the distance, getting all emotional about nothing, silly girls.
Then comes the Supreme Court decision, and perhaps some people they know and love or respect agree with it, so they have a little think and the penny drops.
Ah, well, no of course TW are not actual, literal Women! It’s a courtesy we extend to show we’re allies, but it doesn’t actually mean anything concrete….!