Like I said before, I was really into the classic Doctor Who series when I was a teenager. For a few years my favorite Doctor was Colin Baker's Sixth Doctor just because out of all of them, he was the most loud and weird, and when you're a teenager that sort of appeals to you.
Of course then I grew up. Also I actually saw some of this stories. When you're only reading the novelizations of the stories you interpret character differently than they actually are. Colin Baker had the bad luck to become the Doctor in the mid-eighties when they tried to experiment with stuff to make the show better. New episode lengths that screwed with pacing, trying to make the Doctor an unlikable anti-hero with touches of dangerous psychopathy, and a wild insane costume that clearly brands him as an outsider not afraid of declaring that fact. Out of all of it I only like the costume which I found charming.
So essentially this toy is an embodiement of everything I like about the Sixth Doctor. That he's a guy who says "up yours" to the status quo regardless of silly it makes him look.
Incidently, if you listen to the Doctor Who audio plays put out by Big Finish, they figure out how to make the Sixth Doctor work by presenting his manic insanity as an aspect of his uncompromising dedication to nonconformity.