Ugh - this is an ugly incident all the way around.
Speaking as a military veteran myself, I don't see the relevance of his military service. I don't think veterans deserve one iota of leniency or sympathy when they have committed crimes, unless they are suffering from PTSD or other combat-induced mental illness. God knows this idiot was not a WWII vet. This is sheer racist stupidity.
I don't support beating the crap out of him for painting a car but I can't fault the owner for doing it (especially if, as he claims, the painter was yelling racial slurs). At least he didn't kill him or inflict a life-threatening injury. The owner and his buddy are acting stupid on that video, but they're obviously pumped up by the situation and I doubt they would be talking that way without adrenaline flowing.
Bottom line: this video reflects poorly on everyone, but I see the Navy vet as the worst offender. There is no question none of this would have happened but for his racism. I appreciate that he is acting sorry, but he's doing it only after intentionally damaging someone else's car and getting a beating.