He had a 20-year pure hikkimori phase after quitting high school. Self-admittedly never leaving the room for anything. "Pounded on the wall for food."
It's also not really easy to sympathize with him over what he was doing during the funeral.
I think he made up for it by trying to save the teens from Truck-kun and getting hit himself. Due to the flashbacks, that no doubt took superhuman courage.
If he had continued to creep on Roxy rather than backing away and shutting the door, I think it would be somewhat difficult for me to get past it and not look at him poorly for quite a while.