They don't have to use it as justification. It's the law! If they use something else as justification, but not this, then you can say that. But if they just say

They don't have to use it as justification. It's the law! If they use something else as justification, but not this, then you can say that. But if they just say "This website unavailable due to shutdown" they can be talking about any law, including this one.