In terms of demonyms, I can see that being true (as in 'the Americans' and so on), but I don't really see it in terms of place names, and certainly not countries. We have never had 'the India'; we had the Indies, of course, but that's a simple plural like the Solomon Islands. We never had the Kenya, or the Guinea, or anything similar. I can't really see a pattern where we used 'the' for what we saw as colonies of savages.
In terms of demonyms, we still refer to the French, for example, so it doesn't follow that we use it to refer to our inferiors.
Ahh. Firstly, the construction "The French" and "The Americans" is a totally different issue. That is a term used to describe the population of a nation. One can do it with virtually every nation: the Dutch, the Germans, the Poles, the Italians, the Indonesians, the New Zealanders, the Fijians, etc etc etc. Such a construction has no ulterior connotations.
But that's not what we are talking about here. Instead, we are talking specifically about the definite article being used in relation to an area - usually a geographically-defined area. I am arguing that it has in the past been employed to draw a distinction between the geographical area on the one hand, and any notions of national identity, national culture, sovereignty etc on the other hand. Hence "The Argentine" rather than "Argentina", "The Sudan" rather than "Sudan", and so on.
I suspect that there are specific reasons why countries such as India and Kenya have never directly been subordinated in this way - although it might have escaped your notice that it was extremely common to refer to India and Ceylon/Sri Lanka as "The Sub-Continent" (and anywhere further east as "The East Indies" or "The Orient").
Lastly, as I said in my original post, this is far more subtle (in my opinion) than looking down on "colonies of savages" (re-read my post for the part where I use the word "savages" for clarification). Instead, I think it's more accurately described as an attempt to impose a layer of depersonalisation/denationalisation of these sorts of countries/areas. And what I mean by that (as I thought I had explained before) is a desire - whether consciously or subconsciously - to disavow other countries' sovereign claims (or even those countries' claims to be on an even footing with The British Empire). In other words, it probably made it somewhat more "acceptable" for these regions to be exploited commercially, politically and socially by The British.
Thus (in my opinion), referring to (say) "The Argentine" carries with it the connotation that one is referring to the geographic region equivalent to that bounded by the borders of the nation of Argentina, but without the connotation that this area is a sovereign nation with (for example) its own right to its own resources, its own language, its own culture, its own army/defence, its own colonial ambitions, and so on. Again, I want to point out explicitly that this was (in my view) no more than a very subtle, near-subliminal form of bullying/condescention.