Not that I disagree with your overall point but :

>Recently some African countries have withdrawn from the International Criminal Court on that basis; only the weak are prosecuted

Actually only two (Gambia and Burundi) has withdrawn arguing this. And in both cases, everyone knows the withdrawal is related to their own human rights abuses.

South Africa has announced its intention to withdraw (don't know if it's effective) because they believe it hinders its mediation efforts in conflict zones. (ie. we cannot help Uganda settle with the LRA because we're bound to arrest LRA leaders as soon as they set foot in South Africa)