Some people claim that all cultures are worth preserving, sometimes even that all cultures are equally good. I disagree. For example, I consider the cultures of the Soviet Union and Nazi Germany much worse than the current European ones, and definitely not worth preserving. Culture is a matter of taste, so there is no objective proof that one is worse than another, but various criteria may be defined and used to rank cultures. An example criterion is the (growth of the) Human Development Index of the people following a culture. Different people will emphasise different criteria, and may rank cultures in opposite ways using the same criterion, e.g. some like and some dislike tolerance of sexual orientations that are statistically in the minority.
Similarly, even if a culture is worth preserving, then not all aspects of it necessarily are. Cultures are a mix of good and bad elements. For example, primitive cultures may have great knowledge of local wildlife and weather, but also female genital mutilation, widow strangling, headhunting, cannibalism. A culture may include beautiful art, but also fundamentalist religion that oppresses women and minorities.