I'm don't believe it's against the law to gesture at a police dog, and I'm hearing a distinct lack of a verbal warning from the cop in charge of that vicious dog.
The protester was being a bit of an arse, but the police response was needlessly violent and thoroughly unwarranted - like many of their actions that day.
Absolutely. It was a completely disproportionate response. The guy wasn't attacking or threatening the cops at all.
Yes. But. Before the guy was bitten by Dog 2 he goads Dog 1 and appears to advance towards it offering his arm for lunch. The handler of Dog 1 manages to control the slavering beast, then Dog 2 shoots in from the left and this time the protester's arm is within range. I agree that Dog 2 should have been better controlled, but it looks to me as if the protester really did want to be bitten. He seemed very proud of his wound.