I agree that if U.S. dollars were being sent directly to Kenyan recipients and used only to purchase foreign goods, so that foreign goods were being directly sent from the U.S. to Kenyan recipients, then improvement in measured outcome for recipients compared to non-recipients would be an appropriate metric, and that the decomposition would be perverse. But if the received money, in the form of Kenyan pesos, is being used primarily to purchase Kenyan goods, and causing those goods to be shipped to one villager rather than another while also possibly increasing velocity of trade, remedying inequality, and enabling completely different actors to buy some amount of foreign goods, then I honestly don't understand why this scenario should have the same causal mechanisms as the scenario where foreign goods are being shipped in from outside the country.

As he mentioned, at least one difference is who ends up getting the products, along with the causes of this effect, such as increased velocity, etc... So it does make sense to treat it differently.