I agree there was stupid all around. If the son would have kept his mouth shut I would assign less stupid to team skins. The father was at least talking in a calm voice, though "go ahead" will not help him in court. Team shirts however, showed all signs of being a bully.
The video leaves out some information. Why was the guy taking his trash out with a gun? Nothing wrong with that except all we see is an unholstered handgun. If he were wearing a holstered handgun, that shouldn't cause an eye blink. Maybe the neighbor came over after the mattress was dragged out and started yelling so the father walked out with gun in hand?
I also couldn't tell if angry man charged them or was standing in one place or was walking away. Of course "I'm gonna take that *expletive deleted*ing gun from you" probably gives me some idea.
Anyway, as mentioned above, call freakin' code enforcement.