What? I call bullshit. I used to be a Patent Paralegal for a prominent computer company. You can do a LOT of litigation for $50,000. So unless they are asking for an amount more than that, it's just a nuisance and that's why many of these companies have settled. And you most certainly can try to counter-sue.
Here's what a patent troll does: They go around to smaller and foreign companies, hitting them with some scary patent that *looks* like some basic technology they've been using, and threatens to sue --- or we could settle for $23,000 + future licensing fees and royalties.
The troll goes around long enough to endow their war chest, and then they go after a really big company. Which, by then, they're a little harder to defeat -- but not impossible. Just opt for litigating, then call a patent buster, and they're done. Most tech companies already have a legal team with intellectual property divisions just for this exact scenario.