No, it's not. Anyone can have a gun in the US. The police response is a direct, rational response to this. The US's bad gun laws make it way easier for men to commit suicide in the US, a reason the rates are so high is that easy access to firearms lets men follow through on their impulses pretty much instantaneously.
Suicide by Cop isn't an issue with police behavior, it's a corollary to the individual gun issue. It allows citizens yet another way to have easy access to firearms.
This kid is getting pulled over by 3 cop cars w/ guns pointed at him. This clearly isn't a run of the mill traffic pullover, and whatever they're him over for, he knows it's going to be bad. He decides in the moment to deliberately mime behavior he knows will get him killed. That's not on the cops, that's on him.
So its fair game for the police to blow away anyone that may do something unusual? Old and confused, blow them away. Deaf, blow them away. Having a bad day and are pissed and don't do exactly what told the moment you are told, blow them away. Having been blown the fuck away, laying in the dirt bleeding, in complete shock ears ringing can't hear shit trying to cover the hole the police just blew in your body, blow him away again.