I don't think it is an accident. Quinn thinks political correctness has gone too far. After Quinn comes to school wearing a t-shirt that reads: “I’m MARCHING… ARE YOU?” Guzzo “accidentally” elbows Quinn during basketball practice: after practice, he punches him in the face. So I think Guzzo does not need to be upset. He punched him for no reason even thought Quinn did not say or do anything to him.
Hope this helps!