Torture is a form of mind control, just throwing it in there.
And taking the things a bit further, I find the mysterious concept of the Force fascinating. Not only its secrets, but also the ways it can give you real freedom. For an inquisitor, it would be incredibly useful to have some dark power to read other people's mind. Torture may be recreational for the most sadist siths, but that is an empty action for me, it doesn't give me pleasure. However, reading the thoughts of other people, or changing them forcibly to make them fit in your long-term vision of the world, is more fulfilling