Given the "gift in one hand, gun in the other" history of western actions in Kenya and other African countries over the last centuries, it's hardly surprising there's going to be the random pocket of paranoid skepticism, no matter how good the UBI marketing/education.
I'm personally confused as to why anyone would think it's a good idea to trial UBI in Kenya, as a sort of private charity initiative, given the sordid historical background. It cannot be feasible to get any meaningful data from such projects. There is so much background noise.
Put the funding into microloans or (unfashionable in the west and yet a vital layer in Africa's commercial middle class) labor organization (= unions). Protect the free media and lobby for laws against corruption in politics. Invest in documentation of the continuous crimes against the public interest. Help break the sociopathic power elites that run most African capitals and national economies. Invest in schools. Pay families that keep their children in school. Create demand for local high technology skills, by looking for local partners & experts before flying in foreigners. Name and shame organizations that don't do this. Name and shame national and international companies that overcharge for Internet, for transport, for medicines, for books.
There are surely so many ways to spend money to help Africans continue to break free of the grip of generations of thieves in power (as they are doing in many countries), and pull themselves out of poverty.
In this context, UBI seems... extraordinarily misplaced, and I can't fault people for refusing it.