* Seriously no police or military unit ever trains someone to shoot a person in the leg- it’s a tactical mistake which could cost you your life if you miss, and even if you hit the person it’s not a guarantee that it will stop them.
As far as shooting out tires, again the guy could still drive off on the rims, potentially lose control of the car (with kids inside the car), and also endanger the lives of others. Once a guy like this with a violent criminal record refuses to comply, all bets are off, and he’s assumed to be a threat to the greater community, which includes his children in the car, and any other people driving on the road.
Also, in the US, there are violent criminals with guns, lots of them. That’s why everyone in the entire country knows that when a cop is pointing a gun at you, the best way to not get killed is to comply. I know it sucks, and yes some cops are assholes on an ego trip- I’ve dealt with all sorts of cops, some decent, some jerks, but the one thing that never crossed my mind during any police stop was that it would be a good idea to resist or try to get away. Everyone knows this. I’ll say it again: EVERYONE in the US knows that if cops are pointing guns at you and telling you to stop, walking away and reaching into a car will likely get you shot. All the people in the neighborhood watching know this, and all the people setting Kenosha on fire know this. This guy knew what he was doing- he figured this is the post George Floyd era so he could just walk away and nothing would happen to him.