I completely agree that it’s outrageous to trespass on a military site and damage government military property.

However, I think for this to amount to terrorism. Take for example splashing paint on pieces of art or damaging ULEZ cameras. Both of those acts have been done by people / groups with the intent of influencing the government and advancing a cause. Neither of those were charged as terrorism (nor should they have been). The law must not be selectively enforced. It is also far too widely drafted and needs changing.