I'm not a specialist in the Khajiiti lore and especially in the Khajiiti language, but I think it is a lingual feature, not a social one. If it is so, then it doesn't sound that odd. As far as I know from official Ta'agra (also supported by the developers' commentaries), there is a /desertrain Khajiiti kata emote with a description to it: "Wield a sword in this kata practiced by adepts in the Khajiiti order of Rawlith Khaj." So, "khaj" is either the word for the "desert" or the "rain". The same time our friend Abnur Tharn explained to us, that "Zhan Khaj" literally means the "desert wind" and this book along with Tharn makes us certain that the "Zhan" word means "wind". This all gives us a certain official meaning of the word "Khaj" as "desert".

Now we have to understand, what the word "iit" means. I'm aware of only two official words containing that "iit" part: the "Lhajiito" ("run away": check the Ahzirr Traajijazeri - a wonderful source for Ta'agra appeared in TES IV) and the Tenarr Zalviit pauldron description ("night stalkers"). So, it seems that the "iit" officialy means "runner", "stalker" or.. "walker", because it was also supported by the out of game commentaries given by the devs around 20 years ago that the word "Khajiit" means the "Desert walker", but I don't have the direct link to the source to support that.

So, finally, the word "Khajiit" means the "desert walker" - this is how they call themselves. Thus, it is obvious that all those outlanders who do not live in the desert, should be called as some other "walkers" or simply "walkers" - the "iit". This is what we see in Elsweyr, this is why they call us, outlanders, this way.

P.S. Hmm, I suppose the Maormer should be called something like "Rawliit" in Ta'agra .