As a lukewarm defense of their statement, mass immigration has indirect effects too, it's not merely a reflection on the immigrants themselves.

There is a global rise in far right populism, and a large part of the justification and rhetoric they use points directly to mass immigration policies. There's a myriad of things they blame: crime, demographic or culture shift, economy.

To be clear, that isn't to say they're right blaming immigration. But its existence has put an enormous burden on democracies in The West. Just look at what a promise to get rid of immigrants did to the US 2016+: a captured, sycophantic, authoritarian government that disregards the rule of law regularly. Leading to regular mass protest and public opposition to LEO.

In Europe it's common to see people point to token heinous crimes - that pregnant woman raped into a miscarriage and her attacker given 12 months, the pedophile gang in the UK - and then use the demographics involved to radicalize people (especially young men - see the Alt Right Pipeline).