You don't even bother to respond, if you're reading it at all. You just reflexively say "you've proven nothing" or "you haven't explained."
It's okay, I have small children, so I understand.
I don't need a link to explain to you that everything a government does is authorized by a law somewhere. Every penny spent, every manager hired, every acre of public land bought, every decoration put up was the result of a law either declaring it, or giving someone else the power to do it.
It's called the rule of law.
If you want a link so bad, here:
What is the Rule of Law?
In any event, hanging your hat on the word "law" is silly. It's obvious the First Amendment would be a joke if governments could simply circumvent it by saying their actions weren't really "laws." You're opening it up to an equally absurd claim that the government can do all kinds of things to restrict freedom of religious practice, speech, etc.