While I might not completely agree with Raphael_Amiard he does raise the interesting point that the burden must be on the record industry to prove that they incur a cost (including an opportunity cost) if piracy is legal.
Having said that, I think both of us need to be aware of identity bias here. I don't necessarily support TPB but I do have strong views on liberty and on those who exploit the creative work of others. Similarly, I get the feeling that you have an emotional distate for TPB (based on their attitude) and identify yourself as belonging to the record industry so take the attacks personally.
I think I should make it clear that everyone here who opposes the "record industry" isn't talking about the people who do creative work, the engineers etc. but rather the people who previously had a monopoly on distribution and used this to exploit the creators and sound engineers. These people have lost their monopoly and can now be replaced by technology and so have taken to attacking the new competition. This doesn't just include TPB. It's like Kodak suing digital camera companies because the new medium allows reprints.