The man was a reactionary and an imperialist (to him, "imperialist" was not an insult, of course), and ruthless...but one day, not too many years from now, there will be no one left alive who remembers the Second World War, and I'm concerned at the idea spreading that there was really no moral difference between the Allies and the Axis, or their leadership. Even if what we did was often bad, if you don't acknowledge the difference between bad and worse, you can't make moral choices in this world. If the choice is between bad and worse, the moral choice is to pick bad, and to let worse happen by default is immoral.
Having said that, I agree that Allied actions should always be open to question, and not just made into hagiography--otherwise, what good is the freedom we were fighting for? For example, it was bad, wrong, for the Americans to force its citizens of Japanese descent into concentration camps (FDR used the term) based on nothing but ethnicity. It was worse for the Nazis to not only do the same type of thing, but then go further, and deliberately exterminate such "enemies" en masse in such camps.
I think the point is related to the full context of your quote--what Churchill said in full was "It is sheer affectation to lacerate a man with the poisonous fragment of a bursting shell and to boggle at making his eyes water by means of lachrymatory gas. I am strongly in favour of using poisoned gas against uncivilized tribes. The moral effect should be so good that the loss of life should be reduced to a minimum. It is not necessary to use only the most deadly gasses: gasses can be used which cause great inconvenience and would spread a lively terror and yet would leave no serious permanent effects on most of those affected."
"Lachrymatory" is a constipated way of saying "tear gas;" while Churchill was being racist (as was FDR) and callous, he was advocating what cops do all the time to break up demonstrations, not the use of gasses designed to maim or kill. I agree with you that one doesn't have to make Churchill into a hero, but again, bad and worse. George Orwell, no friend of Churchill's politics, wrote well about this at the time. Oh, yeah, and Kagura is hot.