With the SI's background. I disagree. You were a slave, forced into being a Sith, ridiculed for being an alien (at least if you are an alien) .
the cult you get seems useful, you get LS points for not giving them up and taking what you want, and DS points for making the deal. Sooo...why go DS on that one?
Why wouldn't you go against the established order? They are after all, at some level, responsible for how you have been/currently are treated.
Then to make matters worse you get on a Dark Counsil members bad side, because you did what other Sith do, but not really even though he doesnt want to see, only it's bad because you're an ex-slave/alien.
Not to mention, saving some lives could be beneficial to you. So, know when to kill em know when to spare them.
And on my SW so far, I've had DS options that were, "Yeah. Kill for killing's sake" imo. Not all, but some.