[james0246]

Originally Posted by JustRob

But can they really cast a genjutsu that will be so life-like that it would be like actual peace? I mean, if that's true, why doesn't everybody just allow them to do it? It doesn't seem very evil.

Spoiler for current stuff...:

If raping someone's free will completely and totally for all eternity (or at least until the body dies) isn't evil I don't know what is...

There are no specifics on how the genjutsu will work, or even if it will actually work. The fact that you have to use the moon is already a problem (what with the moon not actually covering the entire planet), but it is also unclear if the world itself will be changed (ala Izanagi), if everyone will simply be comatose (which is what Itachi's Tsukyomi does to its victims), or some other third thing. Whatever the case, the act itself is evil and malicious, so the whys and hows are a little less important.

That being said, these questions can't really be answered, so you might want to find a thread to discuss your questions in a more speculative fashion.