The things that happened in the past were dreadful, I completely agree. There were people alive during our lifetimes who were responsible for war crimes by the Nazis. WWII is very recent history. But upthread, you mentioned things like the Irish Potato Famine, which happed in the 1850s!
I don't really understand how people today can be fixated on things that happened in the distant past. I think that the agenda of people who focus so much on apologies is to humiliate today's Britain for the past. As a British person, I'm not keen on my country being humiliated for things no one alive today did. Apologies are a political issue, whereas you talk as if it's two people fixing a private relationship.
Once Britain makes one apology, the whole world will pile on, and people who hate my country for the past would just love that. Apologies would result in a worldwide laser-focus on the bad parts of British history, instead of its achievements like ending slavery, the amazing feats of the Victorian engineers, discoveries by James Watt and Isaac Newton, its development of modern sewer systems that helped eradicate disease, the invention of vaccines by Edward Jenner that did the same, the fact that Britain offers free healthcare to all, and many other positive contributions that Britain has made to the world.
If the wrongs of the past are focused on by people today, then we should also focus on the good things from the past. Britain did terrible things, and I am sorry. Can you now thank me for jet engines, penicillin, and antibiotics? They are all British inventions. If today's people are going to apologise for the wrongs of the past, then they should also be thanked for the good of the past. Today, we can read our DNA thanks to a Brit, Francis Crick. You're welcome.