Yes, there is, and allergies
There is a difference between dropping leaflets and sending a precision-guided device. If this information is true, then this propaganda tool is more pernicious than anything we've been exposed to. And I have to wonder if this will be a part of the investigations of the 2016 election.
Your immune system analogy is interesting. Pushing it a little further, an allergy is an immune system response to something that it really doesn't need to worry about; it just doesn't know any better, never been taught. Fake news is just such an irritant to the susceptible.
My rule for the last twenty some years of the internet: Do Not Take Online Polls!