I think it comes from people over analysing him

The Illuminati, Aliens or maybe people with common sense who end up buying the toys for their kids.

Who: Me. Why: Why not!

Perhaps the Auditors have hired the Assassin's Guild again...

A proposed question on Skeptics SE: is Santa actually not real?

The kids on the naughty list.

Hey, people spread the lie that Walter Mitty doesn't exist!

Santa has been outsourced

I think it's pretty obvious who is responsible.

....... Assume?

There’s a better real Santa question.

Who: People who does not have chimneys in their home Why: Because Santa comes down through Chimney

Several comments that were not constructive and becoming increasingly argumentative have been deleted. Please keep comments on-topic and be respectful of others.

I think this still has to handle the most problematic topic with santa being real yet adults not believing in him: How could adults not believe in Santa if toys magically appear every Christmas morning? And if they don't believe because they actually have to buy the toys and put them themselves under the tree, what does santa really do? Hows does he delivers the toys if adults buy them?

Does Santa deliver trademarked stuff like iPads, Kindles and Playstations? Does he deliver videogames? Or LEGOs, Funko POP, or Disney Infinity figures? Because nowadays people just want trademarked stuff, not wooden trains (unless it's Lego's new Retro Wooden Train). If so, how does he gets them? Does he buys them to retailer through a legal entity? Or does he have counterfait factories? If he does have factories, how does Apple deal with products with invalid serial numbers? Is the receiver of the gift charged for it? Is Santa sending people to prison?