It depends on the relative power imbalance at this point. If a 20 year old is out at bars going home with 50 year old dudes, then slay queen. If it's 20 year old secretary with 50 year old boss, then there's a much higher chance that the situation is fucked, though still not 100% I suppose.

Oh, I judge, particularly the older person, but not in some moralistic way. But in a "if at 50 you can have a romantic or sexual relationship, even temporarily, with an 18-year-old, I have some unflattering views of you."

Hey is that Oyasumi Punpun?

I couldn't remember the name and I am amused that the search string "sad bird manga" worked.