Brexit has not caused these problems but it has made Britain more vulnerable to it. It could have been navigated if we had a different government from the people in charge right now who did it properly, but had it not happened at all I think we would have fared much better.People going on and on about Brexit when these things are going on all over the world. but the brainwashed still need to parrot Brexit in every post. Brexit was a huge push to divide us and confuse us. Make us unsteady in what we believed. I didn't think you could get more left-wing than me but now I'm apparently a right-wing ignorant racist. I didn't change,the left changed My left might not agree with what you say but would fight for your right to say it. now the left will shut you down over a word. PC was invented to make us unsteady always wondering or worrying if we were going to offend someone. The left love to label everyone and there are so many agendas right there, We are fighting each other over words and labels and while we do that governments are literally getting away with murder.
Also the overton window is a thing. What's considered left changes over time.
However I do agree with you in some ways. Labour activist wing (journalists like Owen Jones who you see on Twitter) focus far too much on liberal social issues at the expense of economic leftism which is turning off people from voting Labour.