I am sure there are plenty that would make that argument, till its their idea that is stolen.
And here we have yet another person who does not understand the concept of theft, just keep calling apples oranges...
I fully understand the concept of theft.
In criminal law, theft is the taking of another person's property without that person's freely-given consent.
Now you might disagree that an idea can be viewed as someone's property, and that can be argued. However, I work at a design and engineering firm (as an IT guy) where we compete for business with other firms. If there were no laws against stealing intellectual property, what would keep me from looking at the design and engineering concepts and handing them to our competitors? These are just ideas, but they will eventually lead to contracts and jobs and money. The same principle can be applied to any field. As far as Thom's statement of freely sharing his ideas with others that would be covered under the "freely-given consent" i.e. open source software.
Now maybe you are saying that its not theft because you are not leaving the person without their original idea (if i gave the idea to my company's competitor, my company would still have the idea also), but this part of theft is called appropriation, or asserting ownership over what is not rightfully yours.
All in all it doesn't really matter I was just implying that if I came up with a brilliant idea to make a pile of money and someone "took" my idea without my consent, called it their own, packaged and sold it leaving me with no profits of my own, it might change my outlook on the subject.