I think this example is an example of cultural relativism since it fulfills the basic principles of cultural relativism. Different cultures will have different moral codes, and there is no good or bad moral code. Every moral code is equal.
The example is talking about infanticide. David says that, in our culture or in wealthy nations, people think that infanticide is morally bad and unacceptable. However, he also mentions that, in some specific culture groups like Inuit tribes, infanticide sometimes is acceptable and needed due to the external factors. The harsh living environment lowers the possibilities for infants to survive. The reason why people have different attitudes towards infanticide is that people have a different cultural background which provides a different moral standard to evaluate whether the action is good or not. At the same time, David also emphasized that there is no right or wrong about this twp different attitude and they are equally important.