Well actually, upon researching it, the loss of Germany's colonies was considered by many to be more insulting and offensive than even the loss of many mainland territories, as it was felt that Germany wasn't being respected as a Great European Pwoer. Hell, Adenauer himself was the Head of the German Colonial Society in the 30s, advocating for their return. It was definitely not a minority view. The Weimar government even worked towards this by sending former plantation owners to Cameroon and having them buy up land to try and steal territory out from under the French.
This rather hits the nail on the head. Yes, Germany sees itself as the rightful Lord of Eastern Europe, but settlement in the East is no longer feasible. Even the only semi-realistic expansion, the Baltics, is understood to have been made impossible by the national consciousness which emerged following WW1 and that it just wouldn't be worth it now.
The difference with Africa is that such colonies were seen as healthy expansions of perceived European supremacy and even as a necessity for population expansion. Even as early the Locarno Treaties, claims of German Colonial guilt were retracted, and the regions were never transformed from Mandates into full colonies because the nature was seen as still open to discussion.
The only real interest Britain had in annexing East Africa was building its precious railroad, and Germany would certainly be willing to respect their rights as long as relations remain good. Yes, this would require a navy, but Britain didn't oppose Germany having a navy--look at the Weimar Republic--they just opposed Germany trying to be a significant naval power, which I don't see this Germany trying to do without good reason. Britain could even use this to their advantage by roping Germany into a role defending their holdings in East Africa, especially.in the event of them being concerned about Italy.