OK I agree with your first point about Justice. It is NOT about justice. But lets not die in a ditch about semantics...
The MAKE POVERTY HISTORY campaign is trying to do exactly what you drive at in your latter point. Sustainable relief from poverty as a result of cultural, political, and geological ruins left from centuries of colonialism.
No one is saying the cause is wrong, I just object to the way that Geldof sets himself up as the moral authority on Africa and if you disagree with what he say's then you're as bad as those damn dictators.