(I'm not the most knowledgeable about these sort of things so if anyone with more experience can correct anything here please do)
I get where you're coming from, but it's a false equivalence. Yeah, you can be treated unfairly in specific situations by girls, but that's not the same thing as oppression. If I'm in a situation where I'm being treated unfairly because I'm male, okay, maybe it's wrong, but I can walk away, and continue my life in a society (and world) where just being male gives me the advantage in most situations. Girls can't walk away from unjust treatment, because that's what they face nearly everywhere. Men hold a disproportionate amount of power, representation, are given more credibility, etc. So absolutely, maybe you've been treated unfairly and that sucks, but it's not the same thing as oppression. Unless you and me are dropped into an alternate reality where men have been systematically oppressed for all of history and are still treated unfairly in a female-dominated world where women are in most positions of power, have most of the representation, are given more credibility and so on, I don't think we'll ever know what being oppressed on the basis of gender feels like.