No doubt those are concerns. But slightly more than half of the voters, voted to leave, and we should try to understand why. While I certainly don't think that being PC about Islam is the only reason, but I do believe it's one of the reasons.
The was considerable shouting about east Europeans (mostly Christian) "coming to Britain and taking our jobs"
Many of the jobs they took were low paid manual labour (farm work, health service porters, etc) that no self respecting brit brit would throw away their hard earned social security checks to take if it meant exerting themselves.
Many of those east Europeans have now left the UK. Because if this, last harvest saw food rotting in the ground because there was no labour to harvest it. This state will only get worse with many supermarkets stockpiling non perishable goods because they expect fresh food to be in short supply.
Also last winter (pre covid) foreign nurses left the NHS to return home with the effect of causing a major advertising campaign offering a £5000 training bonus