Correction: we know it's scary.

When you think about it, that's really what the word "evil" refers to. It's what we call things that are both scary, and that we perceive to be sentient. It's really quite simple.

So yes, a child who stabs kittens, or a person who says they stabbed kittens for fun as a child - both send a chill down the spine of a normal, neurotypical person, because it's scary. And the reason it's scary, is because you or someone you love could be next.

And that's the only intuition we need to protect ourselves from such people, or such so-called "evil" - is to recognize when the desires of someone are totally out of line with our own. There is absolutely no reason at all that we need to invoke some magical, transcendent realm. The realm we all can see and feel right here is enough.

But as I said before, the morality you describe, in which we have to invoke a realm that we have no evidence of - that morality is ripe for abuse.

I'm not sure what your political bent is, and what arguments might therefore sway you the most, but that type of morality is, for example, what causes people to think that gay love is bad. That something can be bad simply because someone from the "transcendent realm" said so. And it's also what enable Zionistic or Jihadist thinking.

In short, it's bad. It enables people to convince other people of moral rules that there is no evidence for at all.

There's a scene in Indiana Jones and the Last Crusade where he's supposed to take a "step of faith" over a pit onto what appears to be thin air. But it turns out, there is actually a solid bridge that's just been painted to look like the pit below. The bridge is solid, but he just couldn't see it until he looked at it from a different angle.

That's, I think, similar to the situation we're in here. The morality I'm describing is solid, and supplies everything we need for a functioning moral code. And you should be able to see it yourself, without actually having to take a "leap of faith". But you have to think about it long enough to see it.