Worldcoin is rich and the average Kenyan is poor - relative to one another. By your logic Worldcoin can't fairly engage with Kenyans - as I summarized your position above "You can't buy and sell from people who are too poor."
If you think that Worldcoin needs to pay some much larger amount, such that some richer population would be equally willing to sell their biometrics, then you are again just reiterating the same idea that it's wrong to do business with poor people. If Worldcoin had to pay what would make the average San Franciscan willing - why would Worldcoin travel all the way to Kenya? They would focus on closer and more familiar populations instead. In reality, they go to Kenya because it's better economics - they get more signups per dollar, and Kenyans are willing to sell biometrics at a lower price.
This line of thinking is a perverse insistence that poor people stay poor because you think their wages are too low. It is morally repellent - you insert yourself in the voluntary exchange of consenting adults in order to prevent them from doing what they want, and it is economically irrational.
I would sell a hash of my retinal scan to Worldcoin. I checked if there was an orb near me - alas, not. Please, tell me, why should I be allowed to make this trade but the average Kenyan should not? Or, tell me why you know better than I do what the hash of my retina scan is worth.