The problem, as I understand, is that a lot of British people don't know all the bad things the Empire did, or don't learn about it the way German people learn about the Holocaust and the Nazi's. Same thing might apply to Belgium - I was appalled to visit Brussels and see a park called "Leopold Park" [1] in the center of the city.
Edit: Turns out this park is named after King Leopold I, the first king of Belgium, and before the Congo atrocities. See https://news.ycombinator.com/item?id=15314232 for the person who educated me :)
On a more personal level, as an Indian person who grew up in the US, I always thought Churchill was a badass dude and a good wartime leader. It wasn't until Middle School that I learned about the WW2 famines and all the stuff he said about Indian people. He hated Indians and was extremely racist. His decisions directly lead to the death of millions of people in India. He's no better than Hitler or any of those dictators in my view, and it's mind boggling that people idolize him as the Lion.
Tangent aside, a lot of people did bad things (globally), but saying the Ottomans are bad or the Belgians are bad doesn't absolve the British Empire of its crimes. I don't think we need reparations or blame anybody today, since we all understand bad things happened, but more people should be educated about what happened and how to make sure it never happens again.