And it's not even that. Her teacher literally praised her cooking when comparing MC's to it, and she took it as backhanded praise. You can't do anything about that...
From what I can see, he just doesn't fit the mold of "listen to your parents/whoever your societal superiors are and do as they say" and that's enough for some to turn violent.
Graaaahhhh!!! J'attendais le cassé de héros avec impatience!!!
Bon, au moins, le démon s'est fait rétamer avec classe, et rien n'arrête Toru. Vivement la suite, est merci pour la trad, Team Clachou!
If they did that, the plot would have been over too quickly. There gotta be some dramatic tension to it, you know. Also, throughout european history, nobles, even when imprisoned, were treated not that harshly.