Chef is upset because of the Scientology episode. Isaac Hayes is a big Scientologist. South Park has madefun of religions for years and it wasn't untilthe Scientology ep that got him upset.
Children ... I did not know that. That explains everything. Why would the article talk about Bloody Mary and ignore this obvious connection?
He personally may not even be upset, but his handlers sure as hell told him he better get away from the show now or suffer the consequences... that's how it is with cults.