What a roundabout way of saying that the MC in his past life is a cold ass because he practiced this technique.
Honestly though, I don't get the purpose of anyone using this skill. Its so "powerful" that we get a bunch of power hungry people going after it. But the "power hungry" are usually that because they feel pleasure in being more powerful than others.
Yet the technique erases their emotions so they don't even feel pleasure. Except anger. Anger is free for all apparently. What an absolutely worthless legendary skill to have.