Unfortunately in reality there is a huge difference between a facility used by one group, and one shared between several. Many community facilities become unpleasant when they are anonymous.
Immigration is only relevant if immigrant communities do not integrate. If it was the cause then you would expect a strong correlation between loneliness and populations of immigrant origin. It certainly does not leap out from a quick look at the numbers: https://www.ons.gov.uk/peoplepopulationandcommunity/wellbein...
The timing of the numbers in the paper do not match either. SOme of them happened in the last two years. A bit recent for desegregation to be a factor.
On the other hand the article does mention a lot of far more plausible possible causes: online only friendships, working hours, decline of religion etc.
What it really is is that some minorities have shittier cultures than others, and some states have handled the integration and assimilation better than others.
Even the USA, for example, is blessed that nearly all of our illegals are Catholics (or more recently evangelical protestants...). Compare this to Europe where it's often muslims who try to bring their Burkas and sharia law with them.
The mass rise of latino voters for trump indicates a very strong effort from America's latino minorities to "act white", to "integrate", and to "assimilate".
I am fine with a multicultural society, as long as it's good culture - and yes, it is quite easy to nearly objectively quantify if a culture or cultural practice is good or not. For example, Americans except for asian americans don't wash their asses with bidets after using the toilet. This leads to swampass/BO, increased toilet paper usage/resource consumption, and far more rectal related health problems. America objectively should change it's cultural practices around bathroom usage.
Unfortunately, cultural critique against bad culture has a tendency for folks to call you "racist", so we aren't allowed to have this conversations with more specificity...
