It’s ironic you mention ‘reality’, since the hysteria surround immigration is largely based on misinformation and xenophobic propaganda being spouted by right-wing politicians and media for well over a decade. This has led to a highly distorted view of the scale and severity of the issue.
First off, the mass migration of peoples seeking refuge from war and other geopolitical disasters is a global issue rather than something that is unique to the UK, but even then the UK has taken in far fewer asylum seekers relative to other EU countries.
There is no evidence that an increase in the rate of foreign-born citizens even correlates with a rise in burglaries, thefts, and other property crimes.
All this is to say that a lot of the anger inflaming these racists riots come from a combination of political and media misinformation and many people’s innate prejudice towards non-Europeans.