Because all of your friends should also be paying 15 quid for that CD - if it were just your friends, it wouldn't matter, but when it's a culmination of people doing exactly the same thing you have people losing millions - people can't make a profit, and that's business for you. The companies release the CD's with copyright notices and the law forces people to abide by if you think copyright law is stupid then blame the businesses for trying to make as much profit as possible, not the law.

If you had the ability/chance to make millions rather than hundreds of thousands, what would you choose?