Could he have hit Rock with a closed fist? Smashed a bottle over his head? Strangled him? Could he have hit him with a baseball bat? Broke a finger? Stabbed him in the leg?
In my personal view, the fist would be at the upper end of appropriate. But there can be no absolutes. I don’t believe any of it can, or should, be rationalised like this. Why do you insist of finding a rule, a principle for this? Not everything can be legislated.
At one point does an act of physical violence against someone who is no physical threat to you become wrong?
I’d say at a point that where the act of violence leaves (or can leave) some kind of permanent damage. There’s always a chance of that, obviously, but I’d say with the first it’s highly unlikely.
If we can at least agree murder is wrong, there is a line over what we could physically do to another person before it become morally indefensible.
I don’t know if anything at all is morally indefensible. Random murder is, I guess. Life is complex.
The reason we like to consider someone being wrong once we breach that physical barrier is because why do we want to dwell in the semantics of how much violence is too much violence? How about we just agree to keep our hands off of each other.
Admittedly, that answers my question above. I think historically violence has existed for a reason. I think (especially given where we find ourselves in terms of the geopolitical tensions) restrictions on WMDs are essential, and if there was a way to get rid of them entirely (blowing them all up in space and all) then that’d be nice (I don’t think it is realistic, though), but other than that, I think violence as a way of defending oneself against slights verbal or otherwise is natural and should be available as an option. I’m afraid if we agree to keep our hands off each other, then we’ll just have even more verbal abuse and no way to, well, shut people up.
I am not claiming to have a rational argument for this, or to be objective, etc.