Right, it’s only a “gotcha” question if you’re not trying to communicate, and instead attempting to score cheap points with your dumber constituents.

You can do the same in reverse by letting a Republican give you their “obvious” definition then forcing them to try to nail jello to the wall by pointing out unintended (even by them) consequences of that, and the people who definitely exist and fall entirely outside their insistence on a binary (even in “biological” terms).

It’s because the actual argument is over who ought to be treated as a woman under which circumstances, not who “is” a woman. But if your audience will allow it it’s much simpler to just pretend the argument is over something else and your opponent is too stupid to define words we use every day.