Checked the video. Obviously depressing. But their view that it is ok to be violent towards individuals when their beef really is with a system that lets many immigrants come here. A ridiculous reaction on their part, but they probably haven't the ability to understand that, or at least not been education to see why it's wrong.
In fairness the guy was trying to say that he didn't consider himself racist generally, but only towards immigrants where he believed it was justified as he couldn't think of any other way to protest. Not that, that makes it any better.
But they would hold their warped views Brexit or no Brexit. If they use Brexit as an excuse then what was the alternative ? Should we have their activity a reason not to do what is right for the country, fearing that they may 'kick off' ?
They need rounding up and educating. But also their fear of what is happening to their society should be understood by the authorities. For every one taking unacceptable, violent action against innocent victims there will be very many feeling things aren't right. One isn't going to solve this by ignoring it, or simply being appalled by it.