I would think breaking through a secured iron gate to be the opposite of peaceful, just my humble opinion. Definitely reason to be concerned and watchful, as it was on a neighborhood and not immediate entrance into private home, however still a bit short of resson to point a firearm.
If they would have been charged by the crowd and were forced to defend themselves I'm not sure which way the jury would go. You cant put yourself in a position to have to use deadly force but you also cant rush and assault someone.... would be an interesting court case for sure. Just my opinion