He gave his opinion not said "you're wrong" so I don't see how it is different. I still don't understand why saying that pisses people off so much to try and flame him rather than just asking for an explanation of his thoughts.

I think it's something more than that. It seems to me that Oro has Kabuto on a leash somehow, or else Kabuto could just run away, or kill Oro while he's weak from not having arms.
Because Kabuto needs Oro, they both have the same goal in mind and that the destruction of Leaf. Oro prob was the one that told him that he wasn't born in Konaha and that Leaf had wiped out his whole clan.
This is the mystery of Kabuto, it would only make sense that he would leave but he seems to have a reason to stay, maybe for loyalty, maybe for a common purpose or maybe he has to. I'm not so sure that he wants to destroy the leaf but is using it as a stepping stone.