I think what katovatzschyn is saying is that, if you've already decided something is true, it's encoded as 'true' in your brain and hence more easily remembered as such, even if you later discover that it's false.

He's saying that if you learn of an argument that shows Fact A to be false, instead of Fact A being deleted from your brain, that argument will be stored as Fact B in your brain. If Fact B is not sufficiently well-integrated in to your thinking then you will pretty much continue to believe Fact A.

BTW don't feel bad that you couldn't understand his sentence, it was pretty hackneyed.