@Crevanille
Legality is not the issue here.
Here you talk about others not knowing the plot, but Rentaro is at VERY VERY minimum about 4 years older than Chiyo since he was capable of saving his uncle from a truck earlier in the timeline than her birth.
"Hahari being funny doesn't make her 'more' acceptable"
At least it makes the plot more interesting. What role does Chiyo even fill that the other girlfriend don't already have down on lock? I mean seriously... The only thing I can think of is "Outrage machine".
"Any complaint you could level against Chiyo could, without a doubt, be justifiably leveled more against Hahari is a walking sex crime waiting to happen. It's only funny bc Hahari is supposed to be seen that way."
And that is what makes Hahari kind-of ok as a concept. The thing is, if we do it with Chiyo, Rentaro is the one who becomes the pedophilic creep (especially since the chiyo case is worse) and if he constantly gets characterization like that, which would be needed in order to take the whole thing seriously, that ruins Rentaro's entire character. The entire plot of the manga hinges on the virtue of Rentaro's character (even more than protags in shonen series like DBZ), and Rentaro's relationship with a barely middleschool girl who's quirk is faking the act of being adult only to burst out crying upon losing her glasses, would simply be too much.
"Nah, I'm gonna have to agree to disagree."
As the one who picked this fight, you have no right to say that.