The racism in your neck of the woods does sound pretty bad and that's horrible. People should be better. However, I'm going to push back a little. At every juncture when we're clashed, albeit amicably, you have insisted upon moving the subject to race - the vast majority of my words are seen as an attack on someone's race, or an attempt to silence someone because of their race. This might be because, as you've said, you have racism shoved in your face - but I'd argue at points you've generalised this into 'any disagreement with someone who isn't white, no matter how reasonably presented is evidence of racism in action'. I don't believe that's the case. For me, as I hope you understand from reading this, the identity of a person is less important than what they have to say. Sure, there may be elements of personal bias thrown into the mix (I am a human being behind this Penguin facade after all) - but for the most part, I go where the arguments lead and I say what I think, without giving ground to anyone based on their immutable characteristics.
As for identity politics, it's certainly being played by the Conservative Right - as I talked about in my Roald Dahl article... but to suggest it isn't being played by anyone else is simply not true. Niche interest groups are inherently right-wing, even if they believe they're Marxists. Here in the UK, identity politics is played by the middle class. It's primarily used as a way for absolute mediocrity to win out. There is nothing more effective in the UK at the moment for social advancement than finding which 'group' you belong to and pushing this agenda. The thing that unites the people doing this is they are all comfortably middle-class. This means instead of getting genuine social advancement in social problems like race, we instead get the Black girl who was friends with others from her private school as the voice of the disenfranchised. It's why you have people like Ms R Stevens (who has long since blocked me) writing about the deleterious effects of racism from her mansion in Europe. It's a middle class game and it's being played for the benefit of the white elite - and it's taking all the oxygen out of the room whilst poor people die. Poor people who in both our countries, are more likely to be Black because of the systemic racism you and I both understand is present.
Racism is the problem. Asking everyone to focus on race isn't the answer. It benefits a tiny minority of people the vast majority of them white. Those that aren't tend not to come from the sort of places you grew up but see social and financial advantage in joining a cause which elevates them personally in the short-term but at the expense of the long term.