(like the more succesful attempts at democracy in Africa, which clearly did NOT come from a mere copy-paste of the Western model, but partly drew on colonial or tribal past)

Perhaps, but the linked articles don't go into enough detail to support this assertion.

perhaps promoting one branch (say, American Protestant radicalism) at the expense of other (say, Southern slavery and its mode of life) but not cutting any memories and ideas off = good.

I would like to point out that decentralized systems, e.g., libertarianism, are better at this then centralized systems, e.g., socialism.