There wouldn't be a No True Scotsman there if they believe that a core principle of feminism is contradicted by someone who doesn't care about male rape or tries to excuse it.
Precisely. NTS is only a fallacy when one responds to a counterexample of a universal (e.g. "Here's a feminist that hates this video") by claiming simply that "no true Scotsman" (or feminist, autc.) would serve as a counterexample (by hating the video). It's a form of circular reasoning, when it's a fallacy.
... Maybe I'm unusually thick today, but I still don't see the lack of fallacy. tla asserts that not all [This large general group] are like [Offensive subset of group] [Offensive subset] would assert that tla doesn't understand [General groups]'s core principles tla says the same thing. Both of them call themselves the same thing (Excluding differentiation between feminist and radfem which is a different conversation methinks). Which one is correct in pronouncing the other's incorrectness? I know what the favorite is, but I'm not sure that it's a defensible position.