Canceled because it imitates a children's show (a theory)
I was thinking about this earlier, and does it feel like the only reason for the cancellation is because it has mature matter in a very child like appearance? I say this because it's not as if there haven't been other shows with strong or "controversial" subject matter (Martin Luther King called everyone ni**ers in a church on the Boondocks, after all, Adult Swim is not new at all to racy stuff).
So I was contemplating it, maybe it's not just what the show has turned to now but because it specifically imitates a Biblical children's show of the past.
Which frankly makes me mad. I'm a Christian myself but even I can see this show for what it is and I think it's a disgrace to get rid of something so genius. Family Guy continues on with all of it's randomness but God forbid a humor show with deep thought runs as well.
"If you should need me, tap this staff three times on a wall."
"Magic?"
"No, it's just loud."