These people weren't "sent to work in Kenya." They already live in Kenya, and are getting wages that are typical of jobs in Kenya.
There is no "what they are worth". There's competition for employees and what they can accept. The same force drives you being paid tens or hundreds of thousands of dollars a year. That's not an abstract "what you're worth". They aren't being kind to you. They're just paying what you'll accept, exactly as they are paying those people what they would accept.
Not to say companies couldn't be a little kinder to some people, particularly when it would cost them so very little. I just think phrases like "what you're worth" only obscures what's actually happening, and makes it harder to understand it.
Certainly we can agree that a person’s “worth” from a full-time job be able to live in an inexpensive 1 br apartment, pay utilities, afford medical care, eat healthy food and purchase basic hygienic items, transportation to work, maybe 1-2 weeks of vacation every year?
in the US, we've collectively decided (through elections) that there should be a minimum wage, from which it follows that we've also decided that the "wages have no bottom" argument, i.e. they should be able to go as low as possible without limit, is unethical and detrimental to society.
Don't get me wrong, companies have an obligation to guarantee some level of workplace safety and healthy conditions etc.! But arguing that it's exploitation to buy labour where it is more affordable is plain silly.
If you fall off a bridge into a river and are drowning, and I'm the only person around, it's still exploitation if I try to make you promise to pay me $10k before I'll throw you the life buoy. It doesn't matter that, counterfactually, the alternative is death. It doesn't matter that you'd be far worse off if I wasn't around to offer you my help (at the maximum price I can extract).
Likewise, the fact that many Kenyans have no strong employment prospects doesn't mean that companies moving their labor to Kenya aren't wrongfully exploiting the situation. And that's leaving aside the fact that centuries of exploitation have created the economic conditions in Kenya. Benefiting from that is something akin to making money off the guy in the river, and it turns out your dad is the one who pushed him in to begin with.
This hinges on the fact that I assume that if you take a job for OpenAI over, say, working at the local market, or your local family business, or doing subsistence farming, ... (I don't know the employment history of Kenyans doing this) you do so because you consider the job at OpenAI, in your own judgment, the better alternative. This assumes some amount of agency in the decision, yes — I would not argue the same if you e.g. forced prisoners to do the work for below minimum wage or whatever and then went and said "hey at least they get two dollars a day more than zero" (I exaggerate). Also, again, this assumes you don't mislead them about the mental toll and then hold them "captive" with sketchy contracts or whatever.
It also seems to me that you have an underlying assumption that companies in the global north could collectively decide to outsource as much labor as they are currently outsourcing, at wage levels matching their "home countries", which I don't think is economically true.
As for your analogy, I think I see the equivalence you draw, but I'm not sure I agree with it. For me the most natural read would be that the "payment" here is the workers' time, the ring you throw is the pay for the job. In that case, the payment (time spent doing some kind of work) happens either way (weird world where you always have to pay for getting saved by some strange law of the universe, I guess), and you're just offering a better ring, or the same ring for less time.
The economic conditions in Kenya were not caused by 'centuries of exploitation' but by millennia of non-development.