1) This is a matter of fact, not of opinion
2) The FACT is that colonialism was far more responsible for arresting development than it ever was for bringing any.
3) Africa was on par technologically with Europe until just shortly before colonialism - heck Africans conquered almost a third of Europe in the middle ages - and brought technological advances with them - they had plenty of technology and scholarship that Europe lacked.
4) Your claims about anthropological reasons are not just unsupported - but proven wrong by the fact that much Africa had superior technology before colonialism, as well as the largest library on earth and cities like Timbuktu which produced the world's greatest peaks of academic scholarship ! This all happened, here, in Africa, before colonialism. 
5) I never said you were a racist, I said it's racist to assume Africans would not have developed the same - and superior - technology, when they provably DID before colonialism.