Honestly, I think that one of the reasons for such scenarios may be that it's easier to try to demolish the idea of there being an actual woman present than accept that she has no romantic/whatever interest in them. And I don't think this is driven primarily by an ego impulse, but by hopelessness.

Of course, there are many other things which factor into such situations (a partially justified caution in the example you've described, for instance, as catfishing can end up being very painful for vulnerable people, even in "milder" forms), like societal norms ("gurls aren't supposed to like icky boy things!"), maybe some elitism, some group resistance, a sort of hazing, etc. But I still can't shake the feeling that even these stem from hopelessness in various ways.

I'm sorry your friend experienced this type of behaviour, and I'm sorry it did some splash damage on you as well... It is, indeed, very disappointing to see such behaviours still being not only prevalent, but even frequently reinforced as standard nowadays... It's a disappointingly hostile world in many places. But if I may point out the silver lining in this, at least nobody can take away your friend's passion!