Actually that's very incorrect. A REAL Sadist would offer aftercare. I'm a sadist and masochist. In the BDSM scene aftercare if very important. Everyone offers it from rope tops to sadists to dominants. At least they should.
As a sadist, it amuses the hell out of me to physically hurt someone. I was shocking this guy's dick once and I couldn't stop giggling as he was squirming on the floor in pain.
Please do some research into the bdsm scene. There's websites and books so there's plenty of knowledge out there.
A lot of people are making statements that are very untrue. Also you don't need someone to be the "one" you to cause you pain. You can if you're into that. There's many ways to dominate people. Not just one size fits all. For example, I'm a sadist yes but I'm a Mistress. You do what the fuck I say or leave me the fuck alone because you're not worthy. Now if someone wants to dominate me then they will have to physically take me down to assert dominance. I'm also a primal. The bdsm world is so huge and there's no one size fits all.