It's interesting that some of the demonstrators are gun owners themselves, but not surprising. There's a widespread resentment of the cops among many gun owners. I find it a bit exaggerated. The fact is civilian gun owners get away with this kind of gun misuse all the time. It's even been defended on this blog with the observation that no one else was injured.
Nevertheless, despite the petty motivations of the demonstrators, they are exactly right. All gun misuse should be punished. If we did that consistently, many second, third and fourth offenses would be prevented.