I would consider the law unjust once it crosses the line into being a burden on society. That's obviously not a black and white transition, although I gave part of what I consider to be over that line in my last response. From my perspective, SOPA, as proposed, was (is?) an unjust law, in that it meets the criteria I specified for what I consider a burden.

It's worth making the distinction between legal rights and natural rights. Obviously, if a particular draconian and unjust law were passed that guaranteed the right to secure your 3kb of data, then you have the legal right to do so. That fact has mostly no bearing on your natural right to do so.

It's also worth noting that sharing between friends and someone making a large profit off of sharing are not the only options. It is not hard to envision a situation with a large amount of sharing and no one profiting directly the way kim dotcom did. It has the scale of the profiteers, but the intent and profitability of the between-friends sharing. I think it is a lot harder to find someone worthy of being called a criminal in such a situation.