It is logically impossible for anyone to believe that "Santa Claus" exists, and for someone to tell their children so makes them an idiot. The fat man in a white and red suit was created by the coca cola company as an advertisement. No matter that he's based off of the christian Saint, Nicholas, "Santa Claus" as such is a myth, an advertising aid, nothing more.
All that rant aside, there are going to be people who believe that lying to their children is the best thing for the whole "season". Though these people really need some counseling, there's not a lot we rational, intelligent people can do about it. It's very similar to the religion debate. There are some people who are going to believe what they're told no matter what. Really, they deserve our pity more than our abuse, no matter how much fun there is to be had at their expense.
All that rant aside, there are going to be people who believe that lying to their children is the best thing for the whole "season". Though these people really need some counseling, there's not a lot we rational, intelligent people can do about it. It's very similar to the religion debate. There are some people who are going to believe what they're told no matter what. Really, they deserve our pity more than our abuse, no matter how much fun there is to be had at their expense.