Kind of disagree with the belief that people "suddenly switched" on Jax after it was revealed she was transfem in the finale. I think it's more accurate to say it was a dial that slowly turned against her as more evidence pointed to her being transfem.
Like, most people liked Jax before episode 5 fine enough, but the second the maid dress scene happened, the second transfem Jax became a more popular reading, people who were fans of her either played contrarian for transmasc Jax or went on about how Jax actually was never that good of a character to begin with. And with the latter, it's very obvious that it's because a lot trans women are becoming fans of the character and they decide to act like a grade school bully by saying what they like is shit.
And this just kept getting worse until the finale where people are now pulling out "Death of the Author" so they can explicitly remove the transfem character from a trans woman's work. Or they do acknowledge Jax being transfem, but only so they can badjacket her as a rapist murderer.
The reactions toward transfem Jax from episode 5 to 8 and then from 8 to the leaked finale, then it being released in theaters, then on YouTube show a subtle, but noticeable tick where people became more hostile toward an increasingly obvious transfem character.