Palestine Action and two further groups were designated as terror organizations because their actions frequently utilize violence and vandalism. While the right to protest and to free speech are the cornerstones of British democracy, violence and vandalism are not, and they have no place in U.K. society. It's the duty of the government to protect the country from this kind of behavior.
Instead of taking action to end Israel's genocide in Gaza, or Britain's complicity in it, the British government is instead going after activists who simply sprayed some paint on military planes. This is a massive overreach which has tremendous impact on free speech and the right to protest.
There's a 10% chance that the Gaza war will end and significant progress be made towards a two-state solution to the Israel-Palestine conflict before Jan. 1, 2030, according to the Metaculus prediction community.