This woman likes set theory because she was involved in a set theory workshop:

https://dmg.tuwien.ac.at/sandramueller/conferences/

But you’re kind of right that it’s not great that math is still a strongly male dominated field. There is not a single woman’s name in the Wikipedia article for set theory, where I first tried to find a counterexample.

Also, you don’t necessarily need set theory to arrive at vacuous truths. Logic is enough:

FALSE => [statement]

Still, I think vacuous truths are fun because they are meaningless. Especially because they have to be considered in math or else your carefully constructed proof becomes invalid.