I think you know perfectly well that billions of people on this planet who believe in some type of religion or deity are neither clinically insane nor psychopaths.
I don't know if you are trolling or are sincere, but you are old enough to start questioning everything you were told growing up and start calling out your father on his BS. Many people raised in a religious household do start questioning it. Many end up rejecting their parents' religious views and come to form their own opinions, sometimes rejecting religion altogether, sometimes embracing a different denomination or entirely different religion, or after much thought or contemplation, coming back to the fold. But the point is that they use their maturing minds to question the "party line"-i.e., their parents' values and beliefs, in order to come into adulthood as an independent thinker. Sounds like it's time for you to do the same. Not that you need to become religious, but you need to learn to understand that intelligent, reasonable, and "sane" people can have belief systems that are completely different from yours, not test-able by science, that you can just agree to disagree on. Things like medical treatments can be tested (though don't discount the placebo effect), so take your scientific mind into nursing or the medical field, but do understand that being disdainful of people for philosophical or religious differences (or even their rejection of scientific facts) will not only make you a less effective caregiver, but also a crappy human being. Stop the cycle of arrogance that you apparently have going on in your household and think for yourself.
You don't have to respect the religious beliefs themselves, but disparaging the people who hold them is just bad behavior and has no place in nursing/medicine.