Liquor and idiots don't mix. Sometimes liquor and decent people don't mix too well either.
Bar owners know this, and there is a high degree of accountability. The onus is on them to keep their customers in line, and when they don't, communities, police, and city councils will turn on them real fast.
Over the years I've heard of several threats of official action against bars because of repeated and persistent barfights and disorderly conduct. A couple of those businesses went away just because of reputation and a loss of clientele. A couple others implemented "No Leather" dress-code policies in a desperate effort to get a handle on the kinds of people who came to their business.
I had a guitar player working for me once who raised his beer to the packed nightclub and said in the microphone, "Get drunk and wreck sh*t!" thinking he was being clever and just feeding the rowdy party atmosphere. Fortunately nobody got too out of hand, but we sure as sh*t had a serious conversation with the bar owner and the police chief after the show.
I'm gonna hang on a limb here and guess that this wasn't the first time the locals have been seriously bothered by patrons of this bar. Trash is trash, Black or White.