You might personally think defence trumps all other things - I don't. Its clearly not unimportant (and I never suggested it was) but defence is, we're told, something we use to protect our way of life and our way of life includes not being called a terrorist for doing something which very obviously is not an act of terrorism.
All forms of protest are under a sustained attack in the UK right now and this is just another extension of that. Sabotaging reality to exert control over a populace is obviously a very much worse thing.
A lot of us are and have protested for years. The previous gvmt didn't care and the current one don't either because its not really about kids, its about control and surveillance. The ruling political class want to know what its citizens are up to and/or want us to know they can id us any time, especially those of us who are noisy about political issues.
Our right to protest is just about gone, including the right to wear masks. We are legally obliged to provide pins to our phones when detained and we can be arrested if a protest is deemed obstructive - which includes being too noisy. We can even be arrested just for discussing holding a protest of some kind.
At the same time, we are told that vocally supporting non-violent groups is now terrorism and can be punishable with prison time.
And the vast majority of the UK population sit on their collective arses moaning about immigrants and watching Love Island. They don't care - genuinely, they absolutely do not care their rights are disappearing one by one.