“When it comes to Diane Abbott, two important things need to be said first. One is that as the first black woman elected to parliament, she will always have an important place in the political history of this country. The other is that, according to one study, she receives more abuse, both racist and sexist, than any other woman in parliament, and by some distance.Yet both of those facts only make her letter all the more dispiriting, even baffling. How could someone with such direct experience of racism show such little understanding of how it works for people who are not the same as her?”