Speaking as a Brit I would say that immigration to my country, going back to Roman times, has done more good than harm, albeit somewhat haphazardly organised in the past. However, these days, there is a system to be followed to obtain legal entry. It must be very frustrating for those who take the time and trouble to follow that system to see the beneficial treatment currently given by the authorities to the illegals who find ways to enter by evading the system. That is what makes people angry, and that is what makes immigration a contentious issue today in many of our countries.