Motorcycle Club members do not have fights over spilt beer, nor do they think 4 on 1 is acceptable numbers.
Bikers may not follow the law, but they do follow their own code of conduct, and severely beating other members is not following that code.
Police aren't more powerful and don't have bigger guns than Motorcycle Clubs. Several of the biggest Clubs have Chapters across the US and Europe, all of whom are subject to the authority of the Club President.
And you can buy better guns than the police have in many states, perfectly legally, never mind the guns that can be bought or imported illegally.