The negative reaction is probably because while you can argue this position from a perspective of wisdom (re impossibility to quantify cultural differences) many Europeans have plenty of prior experience with arguing this from a perspective of ignorance (i.e. failing to consider even basic things like the implications of language differences making you resort to sign language a few 100km from where you live.)

Technically your argument didn't necessarily show any signs of such ignorance, but statistically speaking it would have been quite likely.