THEY ARE PROTECTING THEM, IDIOT, THEY'RE MAKING SURE ONLY THE FITTEST TROLLS SURVIVE. NOT CULLING PEOPLE LIKE ME MEANS ALL KINDS OF FUCKING MUTANTS RUNNING AROUND EVENTUALLY, PROBABLY, AND WHO KNOWS WHAT KIND OF PROBLEM THAT WOULD CAUSE.

[at this point you're too tired and self-loathing and scared to even yell, so you're just going to... drop the volume to a voice that's probably a bit scratchy from all the screaming out loud in short succession!]

...or at least, that's supposed to be why they do it. I. I think they probably do it for fun, too.