Yes, there are weirdoes who do go after everyone associated with that which they boycott. And it should be shunned as weirdo behaviour, agreed.
I'm not seeing a trans community here, but a small group of individuals who believe themselves righteous, charging in the wrong direction. My sight of the happenings is limited as i am an outsider peering through whatever window is available. And this window shows me actors harassed for daring to work on this project or separately, the black actor getting death threats for daring to play Snape as a black actor. That is weirdo behaviour.
You may think you're coming after Rowling's money, but are you really? Do you really think this might not end up as time wasted when the focus could have been on the other, more direct aspects of her hate campaign?
Series and movies have failed when they couldn't enrapture the audience. If this series sucks, it will fail without the ruckus. Instead, if it captivates the audience, this attention will only end up making it even more successful than it would have been. That's why I think this fight is pointless and you're wasting effort. No idea if it's wrong, but it's what I think about it.