Gotta be careful on assigning blame on this one, I think. You're the one who got into the fight, correct? Besides, I tried to break up a fight once, and lost my front tooth (they don't grow back), and another friend attempting the same received ten stitches in his forehead. This was a number of years ago, and a short time before I became involved in the martial arts. Even now, I would hesitate to break up a fight unless someone I really cared about was at risk of getting badly injured. Alot of variables to consider and alot of risks as well.
Actually, I've headed off a number of similar confrontations since then in exactly the same situation. Of course, I've gotten them before blows were thrown but not by much a couple of times. It usually requires people a bit older or more mature who won't tolerate that crap and it absolutely requires some semblance of community on the part of everyone. If either of those are missing you can get serious problems.
There's a book called the Psychology of Persuasion (it's excellent) and one of the chapters involves people's reactions to accidents or crimes. The author points out that people are almost always willing to help (even in New York) if the appeal is direct to them. If they are part of a group and the group doesn't help, they won't help. He tells a story of being in an auto wreck and watching everyone drive by rubber necking. They were in a group, in line and the line kept going forward. He said that to get help he went directly up to people and started asking them to do things (call 911, get a blanket, etc). Everyone helped. Had he just sat there everyone would have driven by watching the blood leak out of him. Think about it and tell me you are different?
Back to my situation, once I've stepped into the beginning's of fights, in general, other people stepped in. The group mindset rules.
PS: I understand your points. I'm not assigning blame to anyone other than myself. I was an idiot on that one.