I must have missed the part where we see that MoR!Hogwarts in general differs in gender politics and sexuality than most of real life, except for the "girls can compete in contact sports/armies with boys" bit, but that's a logical consequence of inherent equality of magical power. Lupin and Harry accepted a Peter/Sirius relationship without any squick, but Harry's a child of the Enlightenment (who, by dint of his uber-prodigy-ness likely didn't have jock-type macho-boys or religious conservatives as his formative peer group) and Lupin's a member of a disadvantaged minority himself. Do we have any evidence that someone like Lucius Malfoy would not be about as homophobic as the average medieval baron, of the sort who would teach his son that raping uppity peasant girls with impunity is one of the bennies that comes with "good breeding?" Or that, say, Seamus Finnigan wouldn't have the same kind of teen-boy homophobia/bullying reaction that's fairly common in our world?