I think the sentiment may have something with the fact as a lifelong tax payer in a country, sometimes one would hesitant to share the resources with those who did not pay the taxes (in this case migrants) in the first place. Additionally, some people may not necessarily have good experience with the guest workers who had been in one's country. Taking these into consideration, I would say quite a few people have doubts about foreigners not necessarily because of innate racial/ethnic prejudice, but because of economic reason and personal experience with guest workers who temporarily stay in their place.
