An interesting conversation here.
But to return to the original item. Why boys with short hair, because it is the fashion perhaps? Girls with long hair, because the feminine looks, probably a choice of RLC. And why young couples? I do not think anyone is interested in a couple of 50. And finally, why the majority of Caucasian race? (in so far that you can speak of a race, but that's another discussion). However, most immigrants in Western Europe are of Turkish or North African countries such as Algeria, Morocco, Tunisia (a.o.) Usually, countries where the habits still far behind compared to Western values. Thus a Muslim girl will never appear in a mini skirt for example. In other words, they are by their faith prudish and will never live in a house where in every room is a camera. Russians appear (only in this regard) then more Western Europeans.