Re: He'as a jerk
You described his business model quite well. On the other hand one of the main purposes of companies is to make money for their owners. One way to create this is to grow and get more and more wealthy, so the stocks price goes up. This works well for a company with a good business model in a growth market. In this case the money earned is best used by re-investing it to further grow the company.
At some point the market might be satisfied and the growth slows down. Now the company has two options. Either try to find new business fields to invest all this money coming in, or starting handing out the cash to stock owners.
CEOs usually go for the first option for various reasons. Investors might prefer the second option, however, as it is less risky.
Icahns business model is to buy stocks of seemingly peaked out companies with lots of cash or other valuable assets and try to convince the other stockholders to cash out. Perhaps not a very nice business model, but at least he is not outright evil.
Other "investors" are much worse, buying good companies, burdem them up to their neck with debt, rip them apart and sell off the pieces. Now, that is evil!