Churchill was a hard-nosed, practical sort. When he set out to destroy someone or something, he was serious and he would resort to whatever it took to complete the mission.
We live in an era where offending our enemies is considered a war crime. So naturally, small-souled men like Olusoga try to drag him down.
One thing that has always puzzled me was how he lost re-election after he had just lead GB through WW2. Amazing actually.