Cruiser21 isn't trying to excuse the behavior of the boys, but is acknowledging that group pressure is very difficult to withstand. I will give my experience in group behavior.
When I was a teen, I marched in a parade that celebrates Israel in NYC. The group I was marching with, were at a side street that was closed off to traffic and we waited a long time to march. As we waited, I noticed that all of a sudden a lot of police were coming into sight and they were locking arms from one corner to the other corner of the street. I was puzzled about why they were doing this. Then I noticed the people protesting the parade. A lot of them were Arabs, yelling slogans and raising fists. So we started yelling back, some curses in Arabic and when our teachers told us to stop we sang songs in Hebrew. There was definitely tension between the two groups, I felt it and then this thought came to my mind. I was thinking that if there was a spark that led to violence I wasn't sure that I would not join in. I did take that mental step back, and I acknowledge that my behavior until I took that step back that I was not thinking, joining in, and even with my thoughts I would have joined. We were a group and it was easy to not think about consequences. At the end of it, no violence or any one getting hurt. I guess that is why it wasn't on the tv news that night, even though I saw the camera filming us.