I'll start by taking a tiny bit of issue with my colleague Scott. I think this will actually be useful.
I interpret the term “truthiness” as meaning not part of the truth that leads in the wrong direction, but rather the presentation of something that is, while not factually true, morally true; that is, it ought to be true. If you disagree with that ought statement, then you are reduced in your moral stature.
It's a way of shifting a debate from the left hemisphere of the brain to the right hemisphere of the brain as a way of mixing up your audience.