Life doesn't have an obvious purpose so people tend to pick up on what others around them are into, so may be into social justice, or greed is good, or islam or

Life doesn't have an obvious purpose so people tend to pick up on what others around them are into, so may be into social justice, or greed is good, or islam or christianity or whatever. Then they tend to clash, fight and blame the other group for their problems. Kids don't really do it but it's why dad has to go bomb the islamists or jihad the infidels or similar.