I think you can't explain away being evil as that. Actions are what determine it. Or determined to do something. Which could extend to how you influence others to act as well. So far he's really tried hard to play the good guy.
Evil also means to have next to no morals, or even take pleasure in others misery.
He's a being of Evil, that is supposed to be Evil in nature, but with his free will he chooses instead to be kind and caring. But at the same time he tries to embrace evil nature and explain away like he did, it doesn't make sense, as he rejects acting in immoral ways or harming others.
If anything it's disingenuous to explain it like he did, unless he really thinks that which otherwise makes it stupid.