I don't think you even know what you're arguing against. You perceive the "trans cause" as being in support of a group that has been presented to you as marginalised and vulnerable, and so worthy of your support.
I've
seen them marginalized and been made vulnerable.
You don't have the first idea of the concerns of the people who are being negatively impacted by this "cause",
That's wrong. I've been involved and studying feminism and LBGTQ issues literally from age 12. Having a concern doesn't make you right. Believing you are being negatively impacted doesn't make it so. It certainly doesn't mean I don't have the first idea of those concerns.
whose hard-won rights are being taken away without any consultation,
Did you not see the march? Do you believe these things aren't discussed in the broader LGBTQ community? You're simply, factually, wrong again. That your arguments aren't
winning, that you aren't given everything you demand, in no way means you weren't consulted, and it certainly doesn't mean the group you're a part of wasn't. They generally don't even agree with you.
and who are being called every nasty name in the book (including by you) for daring to try to discuss the issue.
'Cis' and 'TERF' aren't even in the book of nasty names. You are making up offense.
I think you're in blind denial of the sort of people who are riding along on the trans bandwagon, and the harm they're doing to women, to children and to genuine trans-sexual people. I think this bubble is going to burst in the short to medium term and it will be regarded as the equivalent of the satanic abuse/recovered memories craze of the late 20th century. The reactions will be interesting, particularly as so many people's right-on support of these bullies has been committed to the internet in perpetuity.
So no, I don't think you're insincere, just woefully, ignorantly, blindly one-sided.
More nasty names?
Your concerns are very much of the 'Satanic Panic' type ironically enough. Rationalize my holding my position any way you like; your opinion of that neither interests me nor changes a thing about the arguments presented. It doesn't matter that I think you're having the exact same reaction as white Americans insisting that others gaining rights, acceptance, and civil liberties means you're losing (any of those or other privileges). 'Riding along with'. You know, that is exactly the argument against immigrants. Yeah, there are trans people who are ******** and even sexual predators. This is because, as most everyone knows, trans people are people. Some even like pineapple on their pizza.
You're on the wrong side of history, and it isn't even like it's a hard call anymore. I wish I could say your position is even an extreme for TERFs, but it's pretty middle of the road there.