Laws aren't absolute; they are, when properly written, the codification of social mores. Presently, copyright law conflates copying with theft, you are correct in this. But I think the meta-debate surrounding the issue is whether this assumption is correct; it is thus circular to cite the law as one's defence.

"I think it's silly to fight a law by disobeying it"

I agree with the sentiment that this should not be a first response. But if the intent is to deprive the studios of revenue while sticking a finger to them with the intention of encouraging them to back down, then it is a valid strategy (with precedence). Given the radicalisation of the MPAA, however, I don't see that as being likely.

So I agree with you in practice, but diverge in principle.