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.
Continuity mistake: Just when Peter tries the web launcher the tables and chairs on the street change number and position through shots: They are arranged parallel to each other and have the following amount of chairs: First table has 3 chairs, second 2, third 1 and fourth 2. In the close-up, all tables have 2 chairs; the first three tables are parallel, yet a fourth one is behind the third table. Peter also knocks down a table or chair which appears standing in the final shot.
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