I think this is what people forget. In certain areas of London, integration has worked, and the middle classes come from all backgrounds and ethnicities, because there is a lot of wealth in those areas and therefore aspirational families from all backgrounds.
However in some areas this hasn’t worked - there was a lack of wealth to start with, so both ‘sides’ have become embedded in their cultures and roots, because there’s little to unite them in the way of work and aspiration. The white working classes blame the immigrant communities, and in return the immigrant communities think fuck this and double down on whatever their cultural roots are, both in competition with the other.
People in scenario 1 think ‘well we’ve managed to blend in seamlessly, so the fact they haven’t in scenario 2 means they’re just not as great/moral/clever as we are, and just inherently thick and racist’. It’s a badge of moral superiority to think they’re obviously just a better type of person rather than wonder, ‘if I was in scenario 2, and grew up on a council estate, would I think differently?’. It’s more about them patting themselves on the back than concern.
The answer, rather than simply trying to extinguish dissent when it happens and then forget about it only for it to come back stronger, is to address the problem. Could they get ‘representatives’ from both sides together who are willing to discuss? Is there any common ground to be had? Why do each side feel the way they do? We should loosely follow the peace process in Northern Ireland.