People against immigration are mostly racists. They oppose immigration by other races or cultures, but find no fault with immigrants of «their own kind». People against immigration in Northern and Western Europe, for instance are not against immigration of white Swedes, Norwegians, Danes, Germans and Brits, while rampant racism paints Arabs and black people in the worst possible light in an effort to keep them out. There is no rational reason for this hatred, but it is still there, blowing like an ill wind in a given country, ruining it from the inside.
There are a few anti-immigrant people that are against all immigration. They are nationalists and not much better…
Should we treat racists, people against immigration with respect, treat them as if they matter? My answer is a resounding no. If there is one single type of people that doesn’t deserve any consideration it is this. They should leave, not those they viciously attack.
If you think it matters, in any way if your ancestors have lived in a given country for many generations you couldn't be more wrong. The important is what contribution you make, and a top asshole like you contributes only a beyond unpleasant stench.
Immigration and the subsequent influx of new, different cultures are a great benefit to a given place or country. Long live multiculturalism!