Board Thread:Theories and Speculation/@comment-26119997-20150219181955/@comment-6769189-20150220005522

Feeding on blood doesn't necessarily mean it is an inherently evil plant. Plants feed on the remains of Nutrients of dead creatures to survive. This plant was obviously special but it never attacked anyone. We also don't know what effect other kinds of blood has on it.

Absolute power corrupts absolutely. All that happened was she let the power go to her head. We have also seen merging with the tree makes you stronger. The White Zetsu were under her control, she could take back that chakra whenever she wanted to.