I agree with everything you said but the dude is acting like a little bitch, too. He's spitting in people's food and then not expecting any kind of retaliation. Where I come from you don't spit in a person's food. You spit in my food you better hope the least I do to you is break something that belongs to you instead of your fucking legs.
You don't spit in another person's food, ever. I would fucking kill someone if they came up to me and spit in my food. Fuck the stupid guitar.
Not only that, but he is creating a ton of drama and acting like a child by going out there and singing and shit. It's a game of "who can push whose buttons the hardest without offending them" and it is fucking stupid. I don't play those dumb games, you push a button and we are going to fist fight. His fault for getting into those dumb ass games with a girl and not realizing he can't win because he can't fist fight her.
If you want to engage in verbal abuse with some dumb bitch then by all means go right ahead. I have no problem yelling at women and making them feel stupid when they deserve it, but once you take it past verbal abuse by spitting in food, all rules are thrown out the window and the conflict becomes physical.
That said, I would never ever ruin another person's property, either. I believe fist fighting really solves everything - win or lose. And if that is out of the question because you are in a conflict with a chick then all you can do is keep it verbal or walk away.