That's not a strong argument, IMHO, since it would similarly condone any other law-breaking activity where the perpetrator disagrees with the law. It's not as if copyright wasn't controversial before or the IA's actions here have any realistic prospect of moving the needle.

If you're talking about civil disobedience, that's a different matter, but one of the key things about effective civil disobedience is that large numbers of people have to break the law and accept the penalty in order to overwhelm the system and thus show that the law does not have popular support.