Sounds also like the "mob mentality". Maybe if it was just one drunk , he may not have been belligerent.
I like to get ripped now and then and even if my friends and I were faced with this, we would'nt get belligerent. Some people are just that way.
I bartended for 7 years ( in nice restaurants )and could usually tell pretty quick after a person had drank just a couple of drinks if they were likely to be a problem.
I think you did the right thing. Some people over a minor accident like that, dont want to report it to insurance, thus no need for a cop.