Boundaries characterize much of africa because they were created by colonizers who ignored cultural and tribal differences across space.

This is true. Many of the African problems between ethnicities and tribes were caused by borders which were implemented by Europeans who colonized it and who didn't respect the boundaries of culture and tribes and thus divided it wrongly, causing harm to many.

Yes, the boundaries of various countries in Africa were influenced predominately by the political ambitions of foreign colonizers, and were minimally influenced by the cultural and tribal differences divided across spaces, leading to conflict across these borders by native persons.