"they seem to have only targeted right-wing (presumably) Americans."
No, the trolls targeted both camps to stir division - to get the best burning flame you need at least two components, each feeding the other. The final aim was to help Trump, but they also needed to stir up the other side extremists to male that side look more dangerous - and most of them took the bait too. Extremists first act and then think.
Biting the hand that feeds IT
