“Exactly. Supposed they HAD bought beer. Is it now OK to shoot people for illegally buying beer?”
The issue isn’t shooting them over beer. If someone offers deadly force to a cop stopping them, the original crime is not relevant.
But undercover cops don’t seem to get it. I’m not offering deadly force to a cop making a lawful stop. In my mind, I’m killing a rapist/mugger/killer. Even if I’m guilty of the crime, you’re anything but a cop to me. Take the blue colored glasses off and examine yourself from outside.
The issue of their aggressiveness come how small the crime was. Is underage drinking worthy of that initially aggressive response? Is the world going to end because they get away?