If patents help society, then patent trolling is not always a destructive process. In fact it's how things ought to work, if you accept the premise (which I don't). And if it's sometimes a good thing, actually it's not illegitimate to hold in an otherwise unproductive company. It's just like owning a bar of gold: does nothing for anyone, but it's an asset for the owner.
But it's not like gold. Gold is physical - it requires that you do something to obtain it somehow, and it's (generally) clear who rightfully possess that particular piece of gold at any given time.
Patents are ideas. Two (or more) people can independently come up with exactly the same idea, sometimes in very different contexts. The patent system rewards the person who files a patent for it first, and in fact, for the patent troll, it's particularly lucrative when other people execute successfully (which generally means they've actually contributed something of value to society).
I don't think I understand your argument. It seems like you are saying that if patents are overall good then patent trolling isn't always bad and I don't understand how that follows.
