Look at the examples that were given. In the cases I used these people are averaging 4'10-5'2 these outcomes are too extreme to be simply based on their genetics. In fact the charts that were listed pretty much prove this. Sanitation is relevant because if it's neglected it can result in infections/diseases which if acquired at certain key points of development can stunt growth. Of course if you have poor hygiene and you somehow manage to never get sick this doesn't apply, but I doubt this is the case for entire populations. I've never said that various ethnicities don't have differences, I'm just convinced that nutrition/sanitation play a much larger role than people tend to think. In this case they can be compared if we're simply sticking to genetics, some people would even argue these differences in outcomes exist simply because of genetics(crime rates/IQ), but that's not true if you don't ignore things like socioeconomic status and education you realize this might be the real issue.