There are protests all the time, it’s Palestine Action (an organisation) specifically that the government is taking issue with.

After Palestine Action damaged business known to be owned or worked in by Jewish people (not all of whom expressed support of Israel), attacked a policewoman with a sledgehammer, drove a car through the wall of a factory with workers inside, had a leader that has expressed support for Hamas, and broke onto an RAF base and destroyed the engines of two jets, the government had them classified as a terrorist organisation.

That means that any support of PA is illegal, even if you’re not involved in anything PA does. Some people think that is an overstep.