I don't understand why it's necessary to make this political. What these guys did is wrong, I see no need to paint those have similar politics with same brush as this person.
The social justice warrior part was brought up by the grad student in question. I'd argue that it was he who attempted to turn an isolated act of bad judgement into a political statement. I am, in response, stating that people who think in terms of labeling others as social justice warriors tend to have shitty politics.