It's not a matter of grasping the concepts, it's a question of how abhorrent the concepts would be to her. It'd be like... ::digs for a moment:: Okay, check out this thread (extreme idiocy warning, there, sorry). The comparison between talking about homosexuality when it's applicable and talking about heterosexuality when it's applicable is a legit and accurate one; anyone who can see the conversation with any objectivity should immediately understand that both concepts are identical. The resident bigot, though, is pscyhologically incapable of accepting the comparison, because to him, heterosexuality-as-legitimate and homosexuality-as-sin is the inviolable, natural order of the world. He simply cannot see "what you do to us is no more okay than if we did it to you;" he gets the comparison, sure, but to him it doesn't make any more sense than saying "humans eating cows is like cows eating humans." He already "knows" that his thing is not like our thing, it's better, so any argument that starts from the premise "but look, your thing and our thing are the same" is going to fail. Bigotry is impervious to reason, that's why it's bigotry.
To pick a milder example, more in line with where Artemis is probably at with her prejudices, consider the issue of last name changing after matrimony. Perfect equality - the woman keeps her name, the man keeps his - is basically accepted in the Western world. There's provision for it, it doesn't surprise people, it's a common question ("you keeping your name?"). The old sexist standard - a woman takes her husband's name - is also still widely practiced and incredibly easy, it's even built right into the paperwork for the marriage most places. But try being a guy trying to take your wife's name, and see how much respect you get, how much wrestling with the government is necessary to make it happen, how seriously people fail to take you and the assumptions they make about your relationship. Objectively, there's zero difference between the guy taking his wife's name and the girl taking her husband's; you might think having the one practice built right into our culture should pretty much make us totally *expect* to see that practice mirrored. But instead, we think of one as fine and the other as wrong.
Would Artemis understand the concept that men could treat women like chattel, absolutely. Would she perceive it as anything resembling okay that one of her friends wanted to participate in that... not so much. Not regardless of her own experiences with Bana sexism, but because of them.