Calling these sorts of incidents 'oppression' trivializes

Look more closely at the context, in particular the description of the experienced internal feeling and the resulting self-suppression of identity. Regarding triviality I refer you to the word "albeit" which prefaces a more than adequate acknowledgement of scope. You may further observe that I explicitly refrained from judging whether the treatment of Will was appropriate or not, much less to what degree it was inappropriate---because getting caught up with how "bad" the people are behaving to the person completely misses the point

You might as well call having to shake hands with a man you don't like 'rape'.

No. I might not. And not just because the scale of the outrage. Primarily because that implies that the man is a "rapist" when we have no indication that it is him who is forcing the other to have the hand shaking (or have sex). If neither the disliked man nor "you" wishes to have sex but for some reason you are coerced to have sex with each other then he is not raping you.