Plenty of these no-go zones exist for sometime, The Bronx, Watts, Compton, South side Chicago. Nothing new under the sun.
Those are the Black no-go zones. The author is concerned with the Islamic ones.
None of those is trying to metastasize itself into a global Cancer, such as a Caliphate.
I remember, in the very early 50s, my dad picked up my mom’s aunt and uncle at the airport in LA and pretended to be lost in Watts for a couple of hours. This was in a ‘49 Buick convertible. I don’t remember if the top was up or down. I do remember her saying “Lock the doors! Lock the doors! He had a good laugh at her expense.
When I was 9 or 10 I rode the Pacific Electric (the Red Car), alone, from Long Beach to downtown L.A. Stops in Watts. Never a problem. So the no-go zones didn’t used to exist in L.A. back in the day.