I'll give it a shot.
Not only are "trans-women" truly women....they're the only women.
The only true women are biologically male who identify as women and only true men are biologically women who identify as men.
(I tried to give a rationale for it, but the more I tried to come up with a rationale, the more it started to sound like something a leftist would actually believe because I started invoking words like "Cisgender" and then realized just leaving that statement as is, is more sufficient and crazy sounding than explaining it)
There is nothing. It's impossible to come up with abhorrent leftist concepts that are so bad you won't find groups defending it.
The Babylon Bee effect-- by projecting just a little further left you aren't making satire, you're predicting the future.
The simple truth will send them all scurrying.