Mantle, I don't understand how you could think light = town and dark = mafia...
Regardless, I see your case against Carl, but most can be said being his playstyle. He hasn't been playing much, hasn't been re-reading much, is not following the game too closely, and could be understood to be reacting to the quotes on him (for lack of attention to other players) and could be understood to be parotting (for lack of proper insight on the game).
Regardless, with the human scan on Carl, as well as the possibility of it not being play-style but scumminess as you say, I'm comfortable voting him.
Vote: Carl