good, let's go ahead and promote colonism. Imaging if Germans won the war and rule the world. Yep! What a world we are living in now!
Even today, there is a significant number of people within HK that want to go back to British rule. Why deny what the people want?
I'm not suggesting it would actually have been a good thing - I find the idea rather sickening. I'm just saying that any historical counterfactual is arguable, no matter how obvious it seems at first. I think it better to point at actual instances of colonialism gone wrong - indeed WW2 still qualifies, and it's not necessary for the Germans to have won to make that argument.