Who is saying that? I'm saying that the african states as they exist are not the products of the colonial powers but of the movements against colonialism. The colonial powers by and large didn't *do* state-building: They wanted to *prevent* it. (in practice, if not in theory and rhetoric)
Very true. If you actually look at how most African colonies were actually run, they were incredibly messy patchworks of recognized protectorates ruled by local monarchs, barely controlled "tribal zones", directly-ruled areas with authoritarian government, white settler communities with different rights and local government, and areas where state-functions were more exercised by extractive mining and plantation companies. You're not dealing with single systems of government, but very ad-hoc and ramshackle constructions designed to operate as cheaply (in both economic and manpower terms) as possible.
It's no real wonder that working all that into a single functional state post-decolonization didn't work very well in many cases.