...I'm talking about initiating physical violence or threat of violence, and I'd like to hear someone make an argument defending doing that...
I lived in several US states allowing me to use violence to protect my property. You [nonviolently] come on my property, I shoot you in the face.
What's wrong with that?
That's why I very specifically wrote "INITIATING" physical violence. Self defense and defense of one's property is not initiation. Can you fucking read or do I have to ignore you again?
I'm not going to argue over exactly how much defensive force is justifiable in a given hypothetical case. There are always borderline cases that will be decided differently in different places, times and circumstances. People have rights, including the right to defend those rights up to the point just shy of violating somebody else's rights.