"Honestly? It depends on how far you think Medaka Box's hax can get through those ridiculous Wings or not."
Aside from whatever metahax you can argue for like that "All Fiction" ability (I know absolutely nothing about Medaka Box outside of powerscaling tbh), doesn't Kami Tenchi, Counter-Actor and Chousin still neg-diff the verse and pretty much any Shonen Jump verse to date, including arguably Bobobo and Dr Slump (stretched arguments for plot manipulation and metahax for those verses aside)?
Some people are impossible to convince of things, no matter how justified you may be in your rationale.
The best thing you can do in that situation is to remove yourself from it, disengage, rather than waste your time and energy trying to stand up to people that aren't going to be swayed by anything you say.
Ultimately you can do whatever you think is right, though.