It's called cognitive dissonance. It's a real psychological phenomenon. Learn to recognize it in yourself and in others

I've linked the wikipedo article, but the short version is when you simultaneously believe in two ideas that contradict each other, you jump through a bunch of mental hoops to make them fit together.

Here, our subject is convinced that all the things he did should have protected him, so the only way he could have gotten the coof was because somebody else wasn't doing their part.