The popular notion that sexual acts should be performed in the dark and under the sheets is derived from the Judeo-Christian dogma that human beings and thus human sexuality are fundamentally corrupt, shameful, and evil. Because this dogma is still widespread throughout secularized Western societies and in secularized equivalents of original sin, it is now infecting and corrupting non-Western societies along with the positive elements on Western civilization.
It’s unfortunate that this is not widely recognized in those societies, but it’s no coincidence – the intellectuals and politicians of those states have found Western notions about the base nature of human beings very useful for furthering certain social/political goals. Much more deserves to be written about this…