AskHistorians

Was the media/church/merchants/scientific community that promoted The Scramble for Africa as a noble cause unaware of the true motives of the European colonizers, or were they all complicit?

It's more that motives are... multifaceted things when dealing with the behavior of entire societies, or modern states. Many members of religious organizations and the scientific community were sincere (if bigoted) in their promotion of European domination of Africa. But once a power imbalance is established, it is pretty inevitably exploited by those who have the ability to do so.

Business interests were the most nakedly motivated by the asserted interests of greed. Many, I'm sure, believed their spiel about brutal capitalist-imperialist exploitation being good in the long run, but ultimately, they would have been uninterested in 'assisting' such a process in Africa save that it promised to be very profitable to them.

The idea of glory and Empire was widespread in 18th and 19th century European polities, and many ordinary people felt that extension of their country's power over other cultures was in some way ennobling. Furthermore, ideas of progress were just beginning to dominate European thinking at this time, and that came with an ugly reverse side - that a lack of progress (such as that evinced by the Europeans themselves not long before the 18th century AD - conveniently ignored, of course) was in some way proof of deficiency that was either intrinsic, or needed to be 'corrected'.