Facebook is full of trolls, agreed. But I wouldn't say it's the breeding grounds of all trolls. That title goes to forum boards like ****** & something awful, where internet trolls congregate by the thousands and get organized. The ultimate goal of many of these troll groups is to troll somebody to the point of suicide. I've seen this efforts quite a few times, yet nobody does anything.
Why? I have no idea.
"Hoy es un dia normal, pero yo voy a hacerlo intenso" ~ Juanes