Heard some of the same, but to a lighter degree, at a Red Sox game also. I've heard a few similar stories about some of the loose language from friends who have traveled over to Boston as well. Considering Boston's past reputation with athletes like O'Ree and Russell dealing with racism, you could see how I wouldn't have the greatest perception of the city based on what I saw.
In fairness again, yes, this could be the minority, so that's my bad, and no way wanted to blanket you or the good Bruins fans in there who are respectful to others. Certain things just hit home with me, so I do tend to have plenty to say about the fans ( of any city) who pull the race card.