If you play a darkside republic player, you'll be insulting people too. I have a light side BH and I can be mean or nice. In any case, the Siths are known to use the darkside. They focus on power and stepping all over people for it, making decisions that bring pain and fear to others. Betraying and killing each other, innocents ect. You don't have to follow down that path, but a majority of the sith around you in your story do.