you assume they do based on fundamentalism but mystics from various religions don't. a persons belief system is based on their culture, a culture is based on environment, most people can't adapt to new environments, migration proves this. this is how evolution works. it doesn't need a definition, a name, it just happens naturally. ideas, things become enculturated and an apple in new england might be a red delicious variety and in new zealand a fuji but they're both apples with different coloration, forms, and even names but still basically apples.
again the cross is one of the oldest symbols in antiquity. it isn't unique because it implies the yoke; which can take two things and harness them together into ONE function. one thing that can cultivate so much more than one and another working apart. that is exactly where the word culture comes from. the idea of planting something, tending it, and watching it grow.
enculturate