The "friend of humanity" that wanted to vandalise (what was) a happy day for many people.
Some people actually like the idea of the wedding, happy people and a nation coming together to celebrate it.
Regardless of your views on The Monarchy, this was vandalism.
As a minor it's unlikely he will get any more than a caution and we should be thankful that his age means he might mature enough to avoid this stupid activity in the future.
At least the Old Bill actually have the skills to detect this activity, a big improvement I'd say.