There is nothing in the imperial record as chilling as the systematic extermination of the great majority of Europe's Jews. - Andrew Murray

Next Tuesday is the 120th anniversary of the birth of Josef Stalin. His career is the subject of a vast and ever expanding literature. Read it all and, at the end, you are still left paying your money and taking your choice. A socialist system embracing a third of the world and the defeat of Nazi Germany on the one hand. On the other, all accompanied by harsh measures imposed by a one-party regime. Nevertheless, if you believe that the worst crimes visited on humanity this century, from colonialism to Hiroshima and from concentration camps to mass poverty and unemployment have been caused by imperialism, then [Stalin’s birthday] might at least be a moment to ponder why the authors of those crimes and their hack propagandists abominate the name of Stalin beyond all others. It was, after all, Stalin’s best-known critic, Nikita Khrushchev, who remarked in 1956 that "against imperialists, we are all Stalinists".

The Salisbury attack is something we got wrong. When it happened, I thought, "Well, probably there's Russians behind this, because of the use of novichok." I just thought it was Russian gangsters — some business interests, and so forth. I didn't think the Russian state was behind it. And we were wrong. The evidence that's emerged since is overwhelming. We misread that. I still think that the line Jeremy was trying to follow, which is, "Get the evidence first and then state sanctions, and so on, rather than the other way around," is a defensible position. You don't run into saying "This is Putin's responsibility" when you haven't produced the evidence of it. In fact, this evidence has now been produced. Had we known then what we know now, we'd have taken a different view, I think. We just didn't think the Russian state would be so stupid and brazen as to do something like that — to carry out a poisoning attack on British soil. I know, given the Litvinenko precedent perhaps we should have done but that never really got sorted out so clearly . . . Up until then we'd still ha[d] a quiescent PLP. We were doing all right in the polls. That started bringing all the doubts about Jeremy and the leader’s office to the surface again.

Hitler is uniquely excoriated because his victims were almost all white Europeans, while those of Britain (and other classic colonialisms — French, Belgian, Dutch, Italian and Wilhelmine German) were Asian, African and Arabs.
That Hitler's regime is seen as the most bestial of modern times is not of course objectionable. What needs to be confronted is the view that the crimes of other great powers of the last 150 years or so, being less lurid than those of the Nazis, can therefore be subject to a more nuanced judgment, in which the deaths of millions of people on the one hand can be offset against the construction of railways on the other.
The British Empire was almost certainly responsible for more human deaths, albeit over a considerably longer period of time, than Hitler was.