Indeed, but when you win the wars you fight, and your empire ends up being dismantled relatively peacefully, there's no need for the populace at large to confront and come to terms with the horrible things done by their leaders in their name. You don't need a truth and reconciliation commission, so you don't have one - you keep moving forward and, apart from in fusty academic texts that few people read, never look at the reality of what was done, only the triumphalist soundbites that are used to reinforce the national identity.
The average Britain has no idea that it was we who invented the concentration camp, which is pretty shameful.
Well, I think one of the reasons why those things don't go beyond the circles of academia is that people don't really like history and its complexity, they like to draw overly simplified versions of history so they can throw those "facts" at each other during arguments.
And we academics are interested in precisely not doing that.
I think that even saying the British "invented concentration camps" is probably a simplification. You need to define first what constitutes a concentration camp, etc... I guess lots of countries and people have used things that could be described as concentration camps, but they will all differ from one another in a way...
Look at this post, people are interested in throwing things at each others' faces, some are trying to show that Churchill was a racist imperialist monster, others that he was the saviour of the world...
What's the point?
I'm studying Northern Ireland, and the British have done a lot of very questionable things in Northern Ireland. But what I'm interested in is not to "count points" and say "OK the British have done this, booo, that's very bad, they're horrible people and should be ashamed" or, "it's all the fault of the IRA and Irish Republicans, if they had not been so troublesome the British wouldn't have needed to do what they did"...
The point is to understand a situation in all its complexity, to try and understand the plurality of points of view and experiences. Of course that makes it very difficult to have a clear-cut opinion on history. But I don't think it's very useful or beneficial in any way to pass judgements on history.