One, democrats have already demonstrated their lack of appetite to protect trans rights.
Two, it's a hostage situation that allows the "left" party to do nothing by just not being the actual villain. It won't win them elections and won't actually help anyone. You can't pretend you're the good guy if you just stand there while the bad guy shoots the people who you claim you want to help.
Three, vote for the love of gods. I don't care if they're the lesser evil, we can still make them change and that's better than active evil. Their strategy of hostage taking might be a losing one, but we can force them to become the actual good guys