The distinguishing characteristic of rationalization is that it attempts to obscure the difference between truth and falsehood so that we can no longer reliably distinguish between the two. For example, a common Christian apologetic claims that we can never know whether, say, the 9/11 terrorist attacks were inconsistent with the idea of a loving, omnipotent, and omniscient Heavenly Father. God is (supposedly) so much wiser than we are, and knows so much more than we do, that we can never question His wisdom in allowing evil things to happen. Even though it might seem obvious that a good Person would have acted to prevent it, we can never know that God was wrong/negligent to fail to intervene, because God might know something we don’t.
The argument, in other words, is that because of human limitations, we can never know what the right answer is, and therefore we can never say that anyone else’s answer is the wrong one. But that’s a false argument, as we can see by looking at the number pi.