I really can't blame them. Yes, it is satire, but I see grandma's almost daily sharing stuff like this on Facebook. At that, I can bet I can find someone on my friends list who shared this article, believing it to be true. And the funny part is, if you tell them it is satire, they will swear up and down it isn't or 'well, it could be true'.
Just go to the comments section on obvious satire pages like America's Last Line of Defense and you'll understand why they have to debunk this stuff.