Firstly, paying someone to do a job is not "exploiting". I mean, I guess it is if exploit is pared down to just mean "use for a benefit", but it is a pejorative in this context, meant to clutch some pearls and virtue signal (in the weird "I'd rather they don't get paid or be a part of this" way). I'm Canadian and to Americans getting skilled work done in Canada is usually cheaper, and I guarantee you we don't see it as exploitation.
But then it argues that "their" language in Nigeria/Kenya -- you know, English -- is being exploited by being "pushed back" on them. Bizarre. Not only does the contention make zero sense from an RLHF perspective, it's spurious and backed by nothing. Some random guy on YouTube said "Oh yeah this word must come from Kenya". Delve? I see this word regularly, and have for decades. The other words -- “Explore”, “tapestry”, “testament” and “leverage” -- are in no universe rare words. They may appear more frequently than random Facebook comments because OpenAI weighted the inputs and put more emphasis on high quality sources where the grade level is a bit higher, which makes infinitely more sense than it being some manifestation of Kenya or Nigeria.
Similarly words and phrases are viral, especially in niches. That words come into or out of favour in some realm like papers on PubMed by itself proves little and isn't particularly demonstrative. We all stand on the shoulders of giants, and we're all aping what we read and what we see, etc.