How can you say that copying from others is stealing? Nothing happens to the original. Stealing is when you shoplift the package with installation DVDs. Downloading and copying from others is called "sharing", which is pretty far away from "stealing".
The point is, that by taking a copy of something the only damage you are really doing is taking some potential profit away from the original company who put much time and money into creating the original item.
You have not stole anything from them as such, buy you have denied them the money they should have got from you.
The counter argument of course is that we know, each copy taken is not in reality a lost sale.
You may have say 3 CD's of the beatles and that's all you want. Their Best Tracks compilation for example.
You may never want any more, but just out of sheer curiosity you torrent the Beatles complete collection, with loads of track you don't really like, would never of bought, but hey, there is just something about having the complete collection.
Technically you have done no-one any wrong or any harm, no sales were lost, but it's still against the law. Not the same law that shooting someone comes under though.
There is, to muddy the waters, another counter argument that has been proven that many of the people with large collections of pirate music are also some of the people with the largest amounts of paid for music also, much of the items they have bought they would never even known about if they had not pirated it in the 1st place and discovered the artist, and then wanted to physically by their music.
At it's most basic level yes, copyright law had been broken, but it's way more complicated in the bigger picture than this.
