Winston Churchill did not commit "atrocities" nor was he a racist. Those are lies, as told by those for whom untruths are both useful and depressingly common.
Churchill was among the greatest and irreplaceable men of the 20th Century, without whom the entirety of Western civilization would have far more likely been overrun and destroyed.
And that is why the Left despises him. He saved Britain, and was instrumental in liberating Europe. He enthusiastically embraced and celebrated Western culture and society.
As for Churchill's defense of the British Empire: was the world freer and better off when it was strong or when it is, as now, a distant memory?