Earlier quoted context omitted.
I agree with you generally but the RAF are part of the state and not meaningfully "capital". If you attack the military then yes obviously you are going to get the book thrown at you. That does _not_ justify going after the people with signs.
They painted the aircraft.
And they videoed themselves doing it and published that.
And the aircraft weren't usable in the Israel-Palestine conflict but were in the Ukraine one. You have to wonder considering the Russian connections of the principal sponsor of Palestine Action: Fergie Chambers. Worth reading up on him.