If I understand correctly, the IQ distribution in psychopaths is not different from the population as a whole.

So, the 130 IQ (+2 sigma) psychopaths are probably intelligent and self-aware enough to hold their "evil" tendencies in check and to succeed.

On the flip, the 70 IQ (-2 sigma) psychopaths probably do not have the self-insight to understand "why" they feel the way they do. Their impulse control will be much smaller, and they are much more likely to indifferently hurt people, commit crimes, and act on impulse.