“Why would another country invite that into their own culture?”
Number one reason is “power through chaos”.
Create chaos then the govt has to step in with more control over the people to stop the chaos.
1. As you mentioned, increase state power through a policy of purposeful chaos created by cultural disruption; and
2. Reduce opposition effectiveness by destroying intelligence levels through the importation of low IQ migrants.
If those who are playing this game can achieve a substitution of the current crop of constituents, while at the same time gain even more power over state apparatus, then it's a win-win for them all the way to their banks & guarded estates.
But it's not just Europe - look no further than the good old USA to see the same exact process taking place under the auspices of the DNC/GOP uni-party and media cohorts.