Gang bangers are criminals.
Alright, I will play.
Let us assume they have not been convicted of any crime.
But the store owner knows that they associate with known criminals and they dress like known criminals and have the culture of known criminals.
You are saying he cannot keep them off his property.
I think the argument you are making would more properly be “all or nothing”. If you allow me on your property, you allow me to be armed. If you will not allow me to be armed on your property, you should not allow me at all, or you take full responsibility for my defense.
It is a pretty good argument.
See post 44.