Culture, customs. Things are just like they are in various countries. Asking why makes little sense. Most customs can be useful in some situations and less useful, even disturbing in others.

That said if you apply for a qualified job in a foreign country you should have some familiarity with the customs of the target country, at least from reading. Otherwise working there might cause quite some difficulties for both sides.

I know what I am talking about. I knew foreign country B from being a trainee there. Later I went to its neighbor country C to work permanently. Given the fact that they are neighbor countries I assumed to know both of them. Well, there were quite some surprises...