That's because "patent troll" is a derogatory term made up by people who are opposed to the very idea of patents. It comes from people who are frustrated by the patent system (often rightfully so) but aren't intelligent or knowledgeable enough to propose real solutions that don't undermine the basis of our economy and instead want to throw the baby out with the bathwater.

It's the tech equivalent of calling someone a communist. It's a valueless ad hominem.