People ought to be free to hold, and express, whatever beliefs they wish. It’s actions that should be controlled, including the incitement of others to take illegal actions.
So holding a banner saying “I support the Palestine Action Group” is illegal but holding a banner saying either “I want our Government to take action on Palestine” or “Everyone, including the Palestine Action Group, has a right to be heard” ought to be ok. Exactly the same applies to a banned right wing group.
I find it odd that the free speech fundamentalists who populate these pages are not incensed about this.