Nope. He acted on faith, and he was proven correct. Leonid is proof that Forsaken are not, by nature, evil.
It may be that Sylvanas’s Cult of Personality indoctrinates the weak into wickedness. It may be that the majority are evil. It may be that she had the good ones killed off, or the good ones mostly killed themselves.
But there is a clear canon demographic, no matter how small.