DOTA
wants Amber Rudd to call him a naughty boy
You seem to be arguing that it's not authoritarian cause the law says so, which seems a somewhat flawed framework.But you seem to judge Britain being Authoritarian based on the fact that these were "activists" who were jailed, when the reality is purposeful criminal damage has ALWAYS been given harsh sentencing.
It's not about what you deem to be a useless object, it's based on the value of the damage.
If the gallery was able to prove the "fancy frame" cost X money, the charge will be reflected on that, regardless of what that object is nor the intention of the person doing the damage.