You say it's beside the point, but the progressive artificiality or civility you say is endangering our species is part of the high-mindedness in question. So you're not really contradicting what I'm saying.

Asceticism is certainly an extreme form of high-mindedness, or uncompromising idealism. But so is aristocratic decadence. It's a question of animality vs personhood. Sex falls on the animal side of our nature, so human sex is liable to embarrass us when we'd rather think of ourselves as higher beings that deserve to condescend to animals.