What you said was "why should Britain have any say in these matters?"; the question of "Did Britain have a need to claim Gibraltar back when?" is a different question entirely, which I am not qualified to answer, having never studied Gibraltar's history. I have studied a little, just a little, of African history, though — and I don't think you would have brought it up as an example if you knew much about it. Because warfare between different nations/tribes/empires/whatever (the terms have been different at various times) was a constant factor. To the point that for some countries, their lives were actually improved by being occupied by a foreign invader. Not all, and certainly not if the foreign invader was Belgium. (Goodness gracious, the Belgian occupation of Congo was a neverending parade of horribles).

But Africa is such a huge continent, with such a variety of countries (each with their own complicated history) that pretty much any generality you can make about Africa is going to be wrong about large portions of the continent, and about large portions of the history of its various countries. It's perhaps not such a good example to talk about an entire complex continent for a simple point, so I should stop rambling on about it. (But I do recommend finding a book about the empire of Aksum sometime. It's fascinating).