Stated by who? I don't think you need a big bad person in the background to orchestrate it personally.

Traditionally European countries have the highest standard of living.

world wide Europeans are a minority. So most people who are entering European countries are not European. And Europeans rarely want to move to non European countries. Except for maybe Japan.

Rich white folk like cheap / slave labor. In America upper class people have Mexican women cleaning their toilets and Mexican men building their houses and picking their fruit.

Maybe there is some evil group somewhere trying to make it worse but it would happen anyway.