I think it has nothing to do with the nationality. there are some salesmen who are rude in their service. I have faced the same problem in Carrefour. this time the guy was an arabic. I wanted to buy a mobile but i was just asking him to demonstrate or I just want to see the functions but he refused he said you pay them he will do that. but at the same time one arabic coupe came and they ask they same mobile and this guy demonstrated this mobile function and everything to this arabic couple (look like lebanese).
I was quiet frustrated and left the shop and I bought the same mobile from out side.

I mean to say there are rude people everywhere in all fields and in all nationality.