The full video tells the whole story. The Catholic kids were waiting for the bus. That's why they were congregated there. There was another group, a small contingent of activists loudly speaking to the students for quite awhile. Some of the stuff that the activist group was saying was racist, gay slurs, and abusive language directed at the them. Some of the kids reacted negatively to the language. Mostly in essence booing or disagreeing with the characterizations. No violence or threats of violence from the kids. A lot of the Fake News media didn't even report on that aspect as well.