That's an unbelievable overgeneralisation. There are lots of theists who understand probability theory and who consider themselves "rational" or even "rationalists". Myself pre-July 2011, Mason "Tailsteak" Williams (who is worth Googling, by the way), et cetera.
There are lots of theists who understand probability theory and who consider themselves "rational" or even "rationalists".
Yes, but in the matters of faith they start with the bottom line, and make up the relevant probabilities along the way to match it.
http://bigthink.com/think-tank/neil-degrasse-tyson-atheist-or-agnostic
Apparently Dawkins and Tyson give a non-zero probability to "God". Which is pretty much what is expected of a rational person. And of course it will be used by theists to say "They aren't really sure!"