In most countries, if you’re in a situation that needs you to shoot a gun, you generally need to have grounds to use lethal force. If you are, where you shoot doesn’t make a lot of difference. There are arteries in your leg, that if hit, does not bode well for you.

Also, if you are in a lethal force situation (e.g. someone coming at you with a weapon) you want to aim centre mass to increase your likelihood of hitting. Shooting down at that angle (towards to the leg) also means the round could ricochet and hit someone other than the target. The “just shoot them in the leg” is very much movie/gaming logic.

All situations that don’t risk imminent loss of life should be dealt with via taser where applicable though, so agreed on that.