"I find this quite pointless, really. Culture, as in culture of a country, is an extremely diverse thing (which makes it so interesting after all), and if one feels the need to type it, they should at least point out which layer of the culture they are typing. I believe one could find layers of all 'types' in every culture."
I agree that there are many layers and subcultures in every culture but I also think that there's no denying that cultures are different from each other. The differences between cultures could be depicted and analysed in many ways, the MBTI being just one of them. For example, it is widely noted that the Finnish culture is much more introverted (as in, introversion is much more accepted, even respected) than the American culture. For Americans, it can be hard to be an introvert, and for the Finnish, it can be hard to be an extrovert. (I feel, however, that the norm here is becoming extraverted because of global influences... and I don't like it. In any case foreigners who come here usually say that the Finnish are quiet.) It is also said that the Finnish people are quite aware of laws and rules and don't want to break them.
I do acknowledge, however, that the culture in Finnish universities or among artists in Finland is probably not ISTJ but something else. The culture of my Finnish family is not exactly ISTJ, either. I'm talking about the main culture-- the culture that everyone is aware of, the culture that foreigners take notice of, and the culture that affects everyone's sense of what they're expected to be like.
Why type a culture, then? For entertainment. For intellectual purposes. For instrumental purposes. I, for one, read just a few days ago that in Native American culture INFP was the standard. That was a curious thing to find out and also a useful piece of information because I'm very fond of some things about INFP-ness and now I know that in order to surround myself with INFP-ness, I could try reading something about the Native American culture.