Unfortunately self righteousness is not limited to those two groups, and there are those withing those groups who arent remotely self righteous. The most self righteous group of people I've ever met are Satanists, closeley followed by the many sub sects of New Age Pagans (who I've found to be the most intolerant frankly)
Sorry, I'm only messing, self righteousness is in the mind of the outside observer after all.