Hershi,
If you own something, you have a right to use it yourself or lend it to another; it’s all part of the ownership of that one item. If you copy something, you have two of the item, although you only bought the rights to one.
Also, I don’t believe that the argument “I wouldn’t have bought it otherwise” can safely be used. As one rov replied to someone who asked about copying, “of course you wouldn’t buy it if you can get it for free by copying it!”