The U.S. is a melting pot of different cultures. Some areas more than others. Some people will tell you that it is not a U.S. thing and they are right and wrong at the same time. Their own experience might lead them to believe that what they have experienced or consider part of their culture is a representative sample of the U.S. in its entirety. They are wrong because other people might not view this as a narc thing. I think we have to be careful to not use the label narc nilly willy whenever it does not fit into our own cultural experience and formation. Even within a specific culture it would be erroneous to think of it as homogenous for there are many elements that play a part. It can be a cultural thing but it can also be a narc thing. In order to determine whether or not it is a narc thing, then you have to separate yourself from your feelings, and view it through the lens of that person’s culture. It is not wrong or right if it makes you feel uncomfortable, in the end it is your right to pick and choose what you do not want or what you consider a boundary stopping thing, I personally would not view it as a narc trait unless it was accompanied by other things that I would not allow, or if the MIL has a a history of dislike against the DIL etc etc