Why do first world coutries accept immigration. Restricting immigration will be beneficial for both the OECD and those developing.

As a Third Worlder I am sick of people around me only looking to escape to OECD countries, legally or illegally. Instead, they would be prevented of doing so and finally begin home struggle against corruption, nepotism and cronyism - the core reasons why their countries (including mine) are poor and some other are rich. On the other hand, native residents of OECD countries will remain safe from job loss and crime boost which is going on in many OECD countries oeing to immigration. Just look at Sweden and how the mass inflow of illegal immigrants is ruiing their system which took centuries to build a society that satisfies almost every resident. Now Swedes are in a constant fear of crime and job loss.