I hear you, Taffy.
I am aware there is serious lack of integration in the suburbs of Paris.
I think Brexit was, in a large part, a reaction against the phenomenon you describe.
And the one million of Muslim refugees that Mrs Merkels accepted is a very large number to handle, by any measure, any where: it's hard for a country to integrate so many people so fast.

But in the USA, where there are 3.3 million Muslims (1% of the population - link below), overall, they are doing well. A few of them have done real bad things in the last year, but - statistically - not more than the supremacists/racists (think of the South Carolina blond neo Nazi kid who entered a church with a gun last year and killed 9 people who were praying, and who had welcomed him).

In Canada, there are 1 million Muslims (https://en.wikipedia.org/wiki/Islam_in_Canada), 3.2% of the population: They are doing well. Prime Minister Trudeau is personally welcoming Syrian refugees at the airport; Canadian families are sponsoring them.

Could it be that their integration/lack thereof has a lot to do with the host country?