They are liberals (in the usual sense of the term, not the American use as a stand-in for "leftwinger") whose whole hammer-and-sickle-in-bio shtick is as much a LARP as being a woman.
This applies more broadly than troons, to a broad swath of people who ultimately agree with the notion that everything in society can be reduced to a transaction, and that this is morally acceptable. They might want the state to provide certain services but they
also don't want the state to take any action to prevent things like sexual exploitation, consumption of recreational drugs and the crime that is associated with it, or even (in the "ACAB" or "defund the police" guises) common or garden violent crime.
Fundamentally you cannot reconcile Marxism, a way of looking at the world that stresses its real and contradictory
material properties and relations rather than accepting
idealised views, with the postmodernism required for transgenderism.
In Engels's view, the oppression of women by men is
the first class oppression.
Queer theorists come along and say that, essentially, men and women are literally the same and you cannot tell them apart, some men have uteruses and some women have penises. It is the most anti-materialist load of horseshit, and has really shown on the far left which groups are committed to a Marxist view of the world (and everything that falls out of that), and which are playing at being leftwing because they enjoy it and it flatters their ego or they want to be a big fish in a small pond or whatever.