Oldboy didn't just ask questions. It made me ask questions of myself... about myself.
I think the connection between sex & violence goes deeper than how repressing the former drives the latter. In the rest of the animal kingdom, from which humans have always removed themselves, there is a much closer link between the two. Consent is generally a non-issue for other mammals. There are no taboos.
At the same time it doesn't escape me how loaded the above suggestion is, especially in light of a presidential candidate crowing about what amounts to sexual assault being a privilege granted to powerful men.
I would imagine is forthcoming release, Handmaiden, is no less challenging.
(edit. note - I should replace a couple of the uses of the word "violence" with "aggression." You can read into that what you will.)