Well, he doesn't say we have to kill them because they are not human, but because lack of empathy makes them evil, because they cannot sympathize with suffering of another being. Since the only purpose of punishment is education, and they are not capable to be educated then...
but, this criterion is discriminating and if we accept it many innocent would perish. In the end only innocent would be persecuted and psychopaths would be on the "witch hunt". Of course it is said that they are not really human, but the fact that they are not human shouldn't be reason to attack them, the reason should be evil they spread due to the lack of empathy. But as I already said, even if they really do spread evil due to the lack of empathy - this cannot be sole reason to exterminate them or discriminate against them, nobody is born white or without empathy of their own will and such discrimination leads to witch hunt. The story about lack of empathy and evil this lack produces is only excuse for prejudice against different and his arguments are based solely on impossible education of people without empathy.
besides there is also something else wrong in his theory- to say the evil is born out of lack of empathy provides amnesty for different "emotionally volatile" who are capable of injuring or hurting someone while they would die for their football club or country - so they are empathic as they shed tears when their team loses the game. Even in lynch, the only reason is empathy as people identify with suffering of the victim so much that they are capable of killing the first person being accused as perpetrator.
Conclusion: Empathy can cause good and also evil which means that the problem of evil is more complex then lobacevski posits and explains. Still I admit empathy can be a good detector of good and evil.
One of possible implications of this theory is that with empathy one is able to recognize good and evil, and although empathy is inborn biologically in people - if some neurons in brain are responsible for it - than good and evil becomes real, not just some abstract human term , since empathy serves us as a sense for detecting good and evil in the world, like eyes serves us to spot the difference between the red and blue color.. But, like we don't kill colorblind person, we shouldn't kill the one's without the empathy.
It seems that each time has it's attempts of simplifying the matter of evil. Before, Phrenology was one of those attempts, actually - the theory how just because of certain scull-shape a person becomes a criminal. That theory was dismissed. This new reasoning based on empathy is certainly an improvement, but neurologists could say, maybe, if humans are capable of developing the empathy by learning or is it really a matter of physiological conditions. If the latest is the case, then still it's not the reason to kill such a person, and I agree that instead we should try to neutralize their bad influence, somehow. And, who knows, it is possible that those persons are contributing to human population, in some way, because the development within the evolution happens through mutations among the breed.
I'll simplify a little: if psychopaths are indeed such a great actors, as Lobaczewski claims they are - why not putting them in theater, in movies and drastically improve those art branches... Anyhow, proclaiming one thing as absolute good and other as absolute bad one, always leads straight into a witch-hunting. And at the end, that hunt produces the absolute evil, but not as evil - human inborn, but the social situation pushes the man, which would be a good man in usual circumstances, to show his worst.
