Much like a computer can have a nonbiological virus so can a brain. A virus that can be removed easily or fails to spread dies out and another virus (religion) replaces it.

It isn't enough to do good to go to heaven, it is a requirement by the virus that you have the correct version of the virus running and you accept it and only it.

Much like a parasite often alters the behavior of the host, as does a religion when people become hostile at just the thought that the virus/religion/parasite may be the wrong one.

When one religious group tries by force to remove the other religion the people will fight to the death protecting their version of the religion, sometimes even if the strain is only slightly different.

It is through understanding this behavior that Christianity was able to succeed with the Jews.

Matthew 5:17 "Do not think that I came to abolish the Law or the Prophets; I did not come to abolish but to fulfill"

The reason for this passage wasn't because the Jesus actually supported the old testament but because people are unwilling to replace their religion, but tell them their religion is true and you can prove it, but you have a few more rules to add and suddenly you have replaced their version of the religion in the only way possible.

The virus doesn't take with a small amount of people, these people tend to question everything by nature and prefer evidence for claims. These people are a glitch in the system called Atheists and often go into technical and scientific fields because if their nature.

Life is short and people are afraid of death, people want nothing more than to believe with every fiber of their being that it isn't really over when their time is up so they don't like "atheists" trying to get them out of their comfort zone and questioning religion. It is THE most uncomfortable subject for them ever. They'll kill and even risk their lives to protect this utopian view of life after death so it is nothing to shave a few people out of their social circle they once called "friend".

In this information age the role of traditional religions will be challenged by knowledge but it is probably true that most people have a "god sized hole" in their hearts because if for no other reason they are secretly terrified of death.

To drjalexanderphysics's friend (just noticed physics in the name) his friend's decision represents more than just a lack of acceptance for drjalexanderphysics's lack of religion. drjalexanderphysics represents his absolute worst fear and something he at some level already knows but chooses not to accept: That some day he is really going to die.