The issue of thinking in shades of gray vs thinking in black and white transcends just morality. It could be applied to any area of thinking. Cognitive Behavioral Therapy considers black and white/all or nothing thinking to be a cognitive distortion. It is such an unhealthy way of thinking that it is believed to be a factor in mental illness. Fundamentalists and extremists tend to think in black and white more so than moderates who tend to think in shades of gray. Black and white thinking is attractive to some people because it leaves no room for ambiguity. Some people cannot tolerate ambiguity. They want clarity, certainty, and no doubts. Black and white thinking also requires much less mental and analytical effort than shades of gray thinking. It’s simple. Shades of gray requires constant monitoring and adjustment to try to figure out where the best range and balance is. It’s a lot easier to just say all caffeine and all alcohol are bad like Mormons do for example. If a situation really is black and white, then great use black and white thinking, but this is not how life and reality usually are. To be against black and white thinking all the time would be black and white thinking. Most of the time, however, decisions are unclear, relative to other conditions, and many factors have to be balanced against each other. This is also true of morality.