From University of Michigan Professor of Political Science Ronald Inglehart:

Culture is not a constant. It is a system through which a society adapts to its environment.

In The Renaissance of Political Culture,The American Political Science Review, Vol. 82, Issue 4 (Dec., 1988), 1223.

I never thought about culture this way before, but it suggests that, if true, then your personal culture, i.e. your collective values and beliefs, is a system by which you personally would adapt to your environment. Which suggests that culture isn't just mutable, but its purpose is to enable the self to successfully transition from one environment to another, in which process the personal culture itself adapts and changes. So to perceive culture is something to be protected or defended is pointless, because culture is supposed to change.