My My..
As an economic immigrant myself, I like to think that I have some idea of the issues associated with the subject.
There is no doubt that two factors do tend to cause some confusion in this debate.
1.. The type of person who migrates is probably a little different than the person who does not. (This is before we consider race or other factors).
2.. When you come into a new situation, you often see things that the folk that have lived there don't. The New Zealand farmers have an expression that I will dilute to "There's nothing like a stranger to make you think". In other words a tourist quite often asks dumb questions that give you a new perspective on what you are doing..
So you have people coming in who are different and asking dumb questions or worse.. seizing opportunities missed by the locals and this is unsettling.
At this stage a lot of people would criticize the locals for not being accommodating. I believe there is a need for folk that just stay and be. They are the folk that underpin society.
Newbies to any society should make the majority of concessions and should respect the contributions made to provide the fertile soils they can till.