Second, Lodsys didn't even "invent" the idea. They purchased the patent and are now using it like a cluster bomb on the entire mobile app developer community.
The fact that Lodsys bought the patent and didn't invent the idea themselves seems entirely irrelevant to this dilemma. Unless you also think that if you acquire someone else's software, you don't have the right to sell it.
Companies that create patents are more likely to invest their time, money and effort into actually making things that will eventually be sold (in whatever fashion). This activity adds value to the economy. While it is possible for such companies to aggressively pursue their patents in the way that Lodsys has, they don't need to do it to survive, and I hope that the people who work there would rather spend time on more productive things. That's not a guarantee, of course.
Companies that merely collect patents, and exist solely to collect and profit off of the patents themselves, do not add value to the economy. They are parasites. Because they have no other way of generating revenue, we can expect them to behave in the way that Lodsys has.
If it was possible to design the IP laws so that patent trolling was not profitable, then I think that would be a good thing. I'm not sure if it's possible - but I think it's worthwhile to recognize that there is a relevant difference.
Then again, they take way more value out of the market, so it ends up being a negative.
Please correct me if I'm wrong, but is Lodsys not just a collector of intellectual property? There's something to say about the difference between a corporation buying intellectual property rights related to its business and a corporation seeking only to sponge off others labor, profits and wit, contributing neither economic activity nor social involvement.