Wow, that's unbelievable. What possible explanation could there be for this?
Of course it is always possible to modulate people’s behaviour through incentives and so on, to achieve a very high probability that they will behave in certain ways.
In this case it seems that the balance was in favor of the protestors.
Pigs can't be trusted. They like to pretend they're protecting people and doing the right thing. But they're just bullies in uniform. Never trust any of them. Ever. "My dad is a cop though and..." no. If there was a single good cop, they would have stopped this. Fucking pigs. Your dad is a pig. Get over it.
Maybe if cops had better training, they would stop something like this and focus on protecting us. But they don't, and they didn't. They're pigs. Don't be another person who buys into the pigs' lies.
It's also the kind of rhetoric that has driven so many in law enforcement into Trumpism.