Probably because Germans have won the "German lottery", Japanese have won the Japanese lottery, People from Syria "lost" the lottery. Many advanced nations in a kind of way "won" the lottery for their people. Many Americans believe Europeans won the lottery vis a vis the US because they think things are much better and more fair there. On the other hand, people from poor countries think America is a lottery and put great efforts at crossing the border...

It also has a "guilt" aspect to it.