It's not entirely clear what the argument which unites them is supposed to be. This unification is always in the mind of the white matry not the person opposing immigration. In the UK polish immigration was opposed, en mass, poles are white.
SUPPOSE there are large numbers of poorly assimilated people in a country, whose culture of origin is very different than that of the host country. What does the minor coincidence of their common lack of european ancestry show, other than to prove the point, they lack such ancestry?
White skin evolved in europe, with the peoples of europe, as with european culture -- that whiteness tracks this culture is a conincidence. (There's less-and-less european diaspora in america -- which, if imported en mass, might also enrange europeans).
The refusal to treat large scale immigration as a cultural and economic phenomneon, to try and insult opponents of this position with a slander of racism -- this tactic doesnt work any more.
All you are doing is driving those people to say, "OK, so its racism. We'll vote for that then." And the result is real racists are elected.
Do you have any analysis of the issues people opposed to large scale immigartion, from non-western cultures, and who would reverse at least some of it -- do you have any arguments that engage the issues they actually raise?
More importantly, you show no signs of actually wanting to understand what people mean when using the term "racism" so there's no point in elaborating further.