Hermione was not a sociopath. Unlike many Slytherins, she did have a moral compass, and there were lines she was not willing to cross. It simply happened that torture was not one of them, at least not when she could justify it. She rarely got her own hands dirty, however. When she had realised that nothing short of prolonged pain would force Umbridge to accept a Mudblood as her boss, Hermione had sent her off to be re-educated by a particularly vicious group of centaurs. Umbridge had returned substantially more docile than when she had gone in.