[*Varda*]

Arguably, Gandalf DID manipulate Bilbo into giving up the ring, but as was already stated, I think the motivation behind the manipulation is what makes it evil, not the action. Not very much is purely evil in itself.

Saruman trying to manipulate Gandalf into uniting with him was manipulation, and that WAS evil. Saruman did not have Gandalf's best interests in mind, he knew that the two of them could not share the ring. He simply wanted Gandalf's power in order to further his own ambitions. To me, that had evil motives, and so in that sense manipulation is evil. Good thing Gandalf is smarter than Saruman gave him credit for.

Whereas when Gandalf had Bilbo give up the ring, he wasn't taking it for himself, and he was doing it for the good of Bilbo and the good of Middle Earth.

It really does all come down to the motives, to simply say 'Manipulation is evil' is far too general.