Riposte
Member
It's a weasel word for calling something racist, sexist, transexist, etc. in a muted, "acceptable" way. It's great because to accuse something of being racist or sexist is something people might reasonably scrutinize, whereas "problematic" lies in a nebulous area where weak arguments can have more leeway.
Problematic literally means "I have a problem with it", but dressed up to sound more meaningful and academically sound (because generally people don't give a fuck if some stranger has a problem with something). It's probably a combination of these two things though.