Yes, I have always said this.

A sudden influx of different tribes of people living cheek by jowl, competing for jobs and other resources within a long-established existing culture will always lead to civil strife...certainly in the short term.

How long did it take the USA to 'settle down', and they had even taken care to eliminate most of the existing population ?

Compound the problem by having weak laws and social discipline, an open door policy to, and an acceptance of extremist religious and political groups who are already fighting each other in their home countries, and you have a recipe for social disorder and a weakened economy.

One of the greatest strengths of the Americans however, was their national pride and their urge to become a single cohesive society within one great nation.

That is something that is now sadly lacking in our country, even when compared to our EU neighbours.