I get that, the manipulator's good at what they do, but I just can't completely absolve the family of blame. And thinking back on it, we weren't shown that Clover directly manipulated the mom and dad but simply used their already terrible personalities (through manipulating the sister). The sister, I might go a little easier on since she was manipulated since what? Middle school?
The sister was directly controlled, like a puppet, hanging onto Clover's every word, but the parents, though the situation itself was manipulated, their responses were genuine.