I have no idea why you were down-voted. It's true: even if, somehow, evolution had managed to at some point kill off all cultures with a certain trait, the same trait is likely to develop again in at most a few centuries.

If somebody has solid arguments against emiliobumachar's point, I'd be interested to hear them.

Maybe the downvote was because it isn't completely true. Nothing can be too fast, or too slow for evolution.

It's only that culture evolves by different means than genotipes, and by those means fitting the norm more than compensates any unfitness caused by health problems. At least at the short term.

On the contrary, I would say that evolution works pretty quickly to weed out cultural phenomena like, say, suicide cults, in much the same way that it works quickly to remove gross physical deformities.