That's a fair point and duly noted, but then pretty much what we're saying is that rationality is subjective, in which case we have no reason to judge people for that anyway.
edit: nor should it be brought up in debate for the same reason.
It's subjective, but you can argue about it if you agree on premises, and if it can be shown that one person is being inconsistent.
For example, you prefer to act as if there is not a floating pink elephant above you. You also prefer to act as if Santa Clause is not real. You also choose to act as if Mohammad is not the one and only prophet of the true God, Allah. You also choose to act as if the holy trinity is not composed of Brahman, Shiva, and Vishnu. You also choose to act as if our souls are not infected by the remnants of alien beings stuffed in a volcano by intergalactic emperor Xenu. You do, however, choose to believe in Jesus.
We can't see any of these things. We can't test their presence. We can't prove or disprove any of them.
What makes me rational and you irrational is that you have arbitrarily chosen one of them to believe in. This is inconsistent, because you have no more evidence for one than you do the other. I am consistent. I believe in none. That is rationality.
And that is why Martin Luther insisted that:
[color="#1C2837"][color="#333333"][font="Arial"]Reason is a whore, the greatest enemy that faith has. - Martin Luther[/font]
[color="#1C2837"]He understood it. He was at least honest. Why can't you be honest and admit your belief has nothing to do with rationality or proof or logic or any of these faculties, and that you don't want it to?