Many people may go through the pretense of believing to ensure a quiet life. This may help to spread their genes, but their skeptical memes will eventually die with them. F ew, if any, creatures are generally suicidal. Creatures generally do their utmost to survive as long as possible, and those situations where they do apparently risk death often involve the propagation of their own genes. The genes survive, even if the individual does not.
S ometimes it can go badly wrong.
In this case, large scale death often results in the death of the actual meme as well as those who carry it. Examples of this include the Heaven's Gate cult, the Branch Davidians, Jonestown and so on. The meme infects a group of people, and they all gather together, causing the meme to inbreed with itself until a mutation for group suicide arises. They're like an epidemic of 'flu virus. The mutant, destructive meme has run its course and burns out, taking the infected genetic and memetic hosts with it.