Continuity mistake: Before the lizard assaults Gwen in the lab, she has her hands on the device with nothing else, but suddenly has the spray bottle and the lighter.
Continuity mistake: When Spider-Man is launched against the library, when he lies on the floor the type of books next to him change between shots.
Answer: If you're talking about after the dunk scene, Ben didn't see it as Peter standing up for himself. Instead, he says Peter humiliated Flash and then finds out he's the same one that punched Peter earlier. So in Ben's mind, this was retaliation or retribution, which is not OK.
Bishop73