Why do Trolls do their trolling?

Some trolls are paid to be so nasty, their job is to widen the divide within the US. Sounds paranoid, but I see it all the time. People who’s profile is not a “personal” page. These pros have many of these profiles & will actually argue back & forth with his/her own profile just to throw out bad vibes. Their goal is to get people who are ordinarily docile riled up so much that they develop combative attitude towards others. Divide & conquer at wholesale prices.