Basic arithmetic fail

An article (in Slate by Shankar Vedantam) on why propaganda is still effective begins:

Barack Hussein Obama has 18 letters in his name. That's 6+6+6, or 666. Get it?

Except that "Hussein" is 7 letters, not 6.  Surely, that was intentional and the author would get to it?  Nope.

Neither the author nor any fact-checker at Slate bothered to check this basic piece of arithmetic!
Which dovetails neatly into my theory of why propaganda persists:  innumerate media people.