I've not seen what Davies has said re disability/evil, just got the gist - but yes, exactly what you say. Also as @MarsLlama says, his opinion of himself is impervious to any opinion but his. He's been like it since Dr Who restarted.
It's a quite repulsive interview, where he's going 'trust me, I'm right, it is always wrong for a villain to be disabled'.
Clearly he hasn't bothered to consult more than one or two wheelchair users... a huge portion of the disabled community pretty emphatically thinks he is wrong, which he didn't check, apparently.

