Well, honestly having been in dorms/suited I can see how the situation happened. Clearly, these incidents happened over months and months. It's very likely that many days went between incidents. As a new freshmen to a school it is very hard to fit in. Most freshmen would just try to fit in. As he said, he wasn't used to racism. He honestly may have thought that they were all okay guys and that they gave him a hard time and he wanted to fit in. Even though my dorms were full of good people I remember by the end of the first week everyone had a nickname; white eric, mexican eric, downstem doug, the hot ra, jenny from the block, etc etc. It seems like these kids clearly had no concept of taking it too far/innate racism from growing up not knowing better and that he always didn't really ever deal with the situation.
In my head (and not justifying any of it...it's sick and it's the problem with kids not getting more severe punishments/discipline at young ages) I see that they gave him nicknames, did stuff like the bike lock thing and then probably also treated him like a friend in one on one situation/most of the time. Even something as simple as the 4 of them suite-mates being at the cafeteria together and someone steps to him and they have his back. That sort of false loyalty goes a really long way to an impressionable freshmen. In some ways it is mind boggling that his parents had to find out for anything to be done about it...but at the same time living through the dorm I can easily see how a random incident here and there may not have given him the courage/felt the necessity to really be a "snitch" and be labeled an outcast. What annoys me more is that other people, the RA, housing authority etc etc did not do a better job of handling the situation. As a former RA I know how easy it is to get students in trouble if they get even a little bit out of line. They can lose their housing, scholarships, financial aid etc. After the first incident the school (don't know the full details of course) should have done a lot more preemptively.