"Outside agitators" could be anything from students' friends to Blac Bloc assholes to right-wing saboteurs, though, and there's no way to know with any certainty. There's also no way to know with certainty exactly to what extent they were behind the harassment of fellow students and the various flavors of lawlessness that took place. Both data points are question marks and there's no way to prove anything one way or another.
Anything to do with Israel/Palestine is a hot button issue that provokes very strong feelings on both sides, and when emotions run high and people are gathered in a crowd, rational thought and restraint are easily consumed by anger and action. Mob psychology and dynamics have been pretty thoroughly studied. It's just how humans are wired. A friend of mine refers to humans as "overclocked apes", and he's really not wrong.
Some of the bad behavior can most certainly be attributed to the protesters themselves, though. Hand waving it away as the work of "outside agitators" is another very human tendency: the desire to absolve one's own "team" (for want of a better term) of wrongdoing. Acknowledging that some on our team made mistakes and behaved badly is uncomfortable, but it's absolutely necessary.
The protests revealed that there's a pretty virulent strain of anti-Semitism active in some cohorts of the left. There really isn't another way to frame the hateful rhetoric and harassment of Jewish students. Hand waving it away as the work of "outside agitators" is a willful refusal to recognize it for what it is and, even worse, a refusal to confront it.
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