Suppose you ask me to compare golden delicious apples with fuji apples, insinuating that I've made some sort of mistake regarding their tastiness.
I reply:
Fuji apples range from an inviting green with the faintest hint of pink to reddish-pink with bits of green, but the most common is green with blushes of pink.
The flesh is firm, crispy, and juicy--especially if you can get one that was more thoroughly tree-ripened, but it is still a crisp and juicy apple even if not.
Fuji apples have a faint fragrance, almost perfume-like, subtle and not overwhelming.
Truly, a delectable fruit!
I think perhaps it's you who doesn't have any sense of apples.
Do you see anything wrong here?
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My point was not that the U.K. has conducted itself flawlessly over the past 70 years. Rather, it is that perspective is important.
The Queen oversaw (i.e. mostly watched what her government did, with a few personal interventions to try to improve diplomatic ties) the independence of Antigua and Barbuda, the Bahamas, Barbados, Belize, Botswana, (British) Cameroon, Brunei, Cyprus, Dominica, Eritrea, Fiji, Gambia, Grenada, Ghana, Guyana, Jamaica, Kenya, Kuwait, Lesotho, Malawi, Malaysia, the Maldives, Malta, Nauru, Nigeria, Oman, Papua New Guinea, Qatar, Mauritius, St. Christopher and Nevis, St. Lucia, St. Vincent and the Grenadines, Samoa, the Seychelles, Sierra Leone, Singapore, the Solomon Islands, Somalia, Sudan, Swaziland, Tanzania, Trinidad and Tobago, Uganda, Zimbabwe, and a bunch of smaller territories.
No single figurehead can lay greater claim to a legacy of decolonization than can Queen Elizabeth II.
She's a figurehead. And it's historical happenstance, mostly, that she was around at the right time to be the figurehead during an era of global liberation, where the people of the U.K. gradually and tardily came to realize how perversely wrong it was to occupy other people's lands, and consequently their country voluntarily gave (most of) them up. And of course if the British hadn't amassed an appallingly gigantic global colonial empire, none of that would have been necessary. And as you point out, there were some quite horrid atrocities committed while fighting insurrections. (Every example you gave was of complex, messy situations--not to say that the U.K. conducted itself admirably, but in no case were there widely-lauded good guys with the U.K. playing exclusively the role of the villain.)
Is it a stellar legacy? Well, not exactly--conducting yourself selfishly and viciously in a complex and messy situation is no virtue. But any implication that the Queen was the colonizer-in-chief is staggeringly wrongheaded when she was in fact the decolonizer-in-figurehead with some important, tragic, and blameworthy exceptions (at the country level).
As just-more-than-figureheads, the British Monarchy cannot expect mistreated peoples to cheer for them or have a polite word for them when one of them dies. Such is the duty of being a figurehead: you represent all the evils as well as any goods of your country. However, if we're giving reflective criticism, we at least should criticize the situation as it is, not a cherry-picked and demonized caricature.