Earlier quoted context omitted.
I understand that you're simplifying, but I don't think social ill is the right word. It's more like a social good which is ill for the copyright holder. The question in that case is balancing the benefit to society against the benefits to the company which claims copyright or intellectual property. It's a social good in the sense that public domain is a social good when society can benefit, but also a deeper social…
You do not mention that the existence of property is meant to benefit the society as a whole. Copyright provides us with blockbusters. We can discuss about fair use, expiration, fines etc, but let's not pretend that STAR WARS would have happend without copyright law.
So this issue of leaked materials being overall good or bad is really a proxy for a deeper argument. If you're starting from the position that property rights are more important than the spread of culture and the availability of material, you can still believe that leaks are overall a social good, one which needs to be sacrificed at times for the greater good of copyright and protection of intellectual property. We have to make these kinds of sacrifices all the time, which leads to interesting situations like this.
Sometimes, the best thing for society is that laws are broken, even if those laws are essentially correct. The perfect society isn't necessarily one that always follows the rules, but one that makes the right sacrifices for the overall good. Copyright is probably the best example of this situation. Even if the laws are entirely justified, there are plenty of situations in which innovation happened because someone learned something from leaked copyrighted material.
It's tempting to believe that it's possible to create a set of rules that everyone can agree to and always create the optimal situation, but in the real world, this never happens. The real world is messy, and sometimes entirely justifiable laws have a net positive effect when they're broken.