You're rewriting history (both of you are). Colonialism in Africa was certainly detrimental and exploitative, and not just by standards of today. The "peaceful transitions" you speak of, included borders and methods of government that were set up for the benefit of the colonial powers, the ramifications of which continue to this day. And while independence was achieved peacefully in some cases, colonization itself was a violent process.
http://trace.tennessee.edu/cgi/viewcontent.cgi?article=1182&...
http://exhibitions.nypl.org/africanaage/essay-colonization-o...