Statutory law not withstanding, no they are not thieves. They are just competitors. Patents are not property, even though they are erroneously referred to as “intellectual property”. They are just monopolies imposed by the government.
I’m not quite sure you understand the importance of the patent system to the inventor who goes through a very long and expensive process to get a patent, this is not the same as filing a copyright and generally takes around $20K for patent searches and filings. There are companies that steal inventions and a lot of the screaming about patent trolls comes from those who have no interest in the patent system like open source software devotees. So either you believe a patent is property just like real estate, and if someone builds on your real estate it’s stealing, or you don’t believe it’s property in which case you’ll have to argue with the constitution since the Patent Office is established in it.
As a more layman explanation of the protection the patent system, offers you can read the story of Robert Kearns who invented the intermittent windshield wipers on your car, http://en.wikipedia.org/wiki/Robert_Kearns. The auto companies wanted to steal his invention and he had to fight them. Was he a patent troll because he wanted to be paid for his creation?
So you’re telling me, with straight face, that if the ratcheting wrench or some other nifty tool is invented by some poor schmuck and Sears decides to just make the hell out of it with no recompense to the inventor, it’s A-o-K?