Space is big, and complex. There's probably no end to moral, political and philosophical wrangling that must take place. The Prime Directive is probably a stone tablet in the lobby of Starfleet headquarters with a picture of the British flag with the caption: "Don't fuck up other planets the way these guys fucked up other countries."
I'm sure citizens of Canada, Australia, New Zealand and, quite possibly, several others, deeply appreciate your in-depth analysis of their condition.
Really, you don't think the
Canadian First Nations,
Australian Aborigines, and
Māori would agree that the British fucked things up for them?
ETA:
Whatever you may think of the European communities Britain transplanted into the lands it stole from their native inhabitants, let's get one thing straight:
The Federation, unlike the British Empire, is not in the business of conquering foreign lands, or importing its people into lands it has taken from their native inhabitants. The Federation, unlike Britain, is not an empire.
That is the virtue of the Prime Directive.
Late coming back to this. Interesting comments by others, but the above seems to be an element of 'Because You Said This, You Must Also Be In Favour Of...'. Not the case - I think the
general concept of the Prime Directive is admirable but, like any other law or principle it cannot be an absolute - there will always be exceptions or special circumstances.
Check the history of any Human tribe / nation / culture (including most of the ones you cite)
or empire. Any human grouping that lasted long enough to have its own history certainly did so over the dead bodies of others - other groups supplanted or driven away or forcibly assimilated or wiped out, dissidents suppressed, and so on.
No one, not even the Chinese themselves, are certain just how many cultures were literally wiped from history by Emperor Chin in the process of founding China. The (in no particular order) Chinese, Persians, Babylonians, Egyptians, Romans, Mayans, Aztecs, British, Russians, Germans, Ottomans, Danes, Polynesians, Mongols, Hindus, Hebrews and many many others have all had their moments in this regard.
Make no mistake, a lot of these groupings had admirable qualities as well, and that should also be recognized.
We might be appalled by a lot of what they did, but in the context of their times, that was how one did business. A lot of them had slavery and/or overly rigid social orders and/or were less than nice about the rights of women or minorities - again, that was how things were done, and we (should) know better now. Doesn't make such things "right" by any means, but to condemn these peoples out-of-hand by our allegedly evolved 21st century sensibilities is narrow minded. Likewise, singling out one empire to blame for all that is wrong in the world.
Judge not, lest you be judged, as they say. I am sure that some self-righteous individuals in the distant future will find amazing things to condemn "us" for - probably including a lot of stuff we wouldn't have even thought of.