I don't think you really understand what devastation such a parents hurtful comments can do to a kid's psyche. It's trauma, needs a long time (and lots of support) to heal and even then it leaves lifelong scars. His mother's words (his only family) lead to a disproportianate self-hate (as his friend remarks), he constructs his reality in that distorted view. To him they're not blushing, they're scared/disgusted of his hated face and his fellow kids aren't really able (yet) to correct that distorted view no matter what they say.

Jadwiga of Poland thinks its cause before his mom died she said she hated his face

because he is a stupid idiot

What can you expect from a genre that's been booming, dont know if it died down though