People lie to themselves, it's the same with the guys waddling around at 250 with 3% body fat.
Without some sort of beliefs, the world is too painful for the truth. People have to tell themselves nonsense lies.
Unless you have a religious structure in your life where you're forced to be honest with yourself and the universe people are always gonna be floating around with incoherent lives.
Our backs are up against the cosmic unknown, we have no idea what's coming, and we all die in the end. People who can't handle that, lie to themselves and they begin living lives of lies.
Thou shall not lie isn't some trivial commandment. Humility and honesty into the unknown is the only way not to be an idiot in this life.