It's entirely fair game to criticism or even discriminate based on culture, because culture is composed of actions. If people act in such a way that you do not like, that's a valid reason not to like them.

Now, we do still need to respect cultural differences where it makes sense and consider the historical context behind cultural differences, such as colonialism.

Nazis used to measure skull dimensions to discriminate on race. How do you measure "culture" of an individual? Just apply a stereotype based on the country of origin?