NTR Online def isn't the game for them if they're looking for non-rapist antagonists. Along with those examples, Kirito's sister is drugged and raped in the first game, and Alice's corruption in part 2 is based entirely around hypnosis. The other side character girl, (the librarian), also has multiple rape scenes.
The friend of Kirito, (forgetting her name, she has a crush on him), is also raped by Inoda in her first sexual IRL scene. Hell, even the mom is blackmailed by Inoda to start her corruption. NTR Online certainly has a lot of coercion and "sweet-talking", (I'd just call it begging and pity), but there's def a lot of rape too. The weakest parts of the game imo. Granted, I'm not even done with part 2 yet, I just reached that previously mentioned IRL scene which is why all this is fresh in my memory. There's probably more examples past what I've said.