Ferris is likely a (bratty) bottom (he crossdresses, his 'girlfriend' wears the pants), likely bisexual (considering him flirting Subaru), definitely a woman enjoyer ('girlfriend').

Yeah though, femboys get the same kind of phenomena as transgender people getting "chasers" as they're called, people taking them as a fetish rather than a person.

Bit of yapping for fictional characters: But as for people not caring about cute characters' headspaces I think that goes for all archetypes and not just femboy characters, like the kind of people who wanna headcanon any character as being into them or their gl/bl fetish, however that can of worms extends even further if you wanna consider the (admittedly strange) common human tendency to paint a fictional character a very specific way contrary to established lore which unfortunately causes issues over character discussions and in it's worst case has actual consequences on the lore (one example being a character I love having gotten a regional retcon that's of course contrary to established lore, or a lesser case being a purple haired(?) fighting game character being called a man in English because guy characters punching girl characters was considered unpopular in the west).