The argument against piracy is that people have the right to be compensated for their work. Consider this argument in the context of medical services. The extreme pirate position is equivalent to expecting doctors to provide cosmetic surgery for free. The extreme industry position is equivalent to saying doctors should let patients die on the sidewalk if they can't pay.
I'm torn on the issue of sharing files, because I've watched its rise over the past 25 years and seen how tremendously it has improved educational opportunities for poorer peoples.