Hagoromo is NOT evil, it's just BZ using IT.

[SageOfTheTenPaths]

There are 10 chapters left, so there is no time for more fighting or new enemies. Kishi has to wrap thing up, and fast.

What we are seeing is an alternate ending, BZ's ending. He's trying to fool everyone to think that the world was saved so everyone can go on living happy ever after.
The IT will be detected by non other than Madara, as he is the only one that has been knocked out since BZ took over his body and thus not affected by IT.

The evil smile at the end was just Kishi's way of showing that something was wrong with this ending, and that something's not right. Keeping the suspense up. Thats all, he's not evil, give it a rest.

 

[patrickscott]

So you think IT is still in effect?

 

[Tomato God]

That would redeem this manga in my eyes...

 

[Sentinel of Light Style]

Sorry, bro, but what you're saying just sounds like a load of bull. It really is over and I wouldn't even call that an evil smile, at best it's a slightly disturbing grin.

 

[3MESSIAH]

that would be cool if it were so