You guys are all getting pissed over nothing. Officially claimed land doesn't mean people can't start there, it means that the said country intends to expand and consume that land. Not that they're going to get it no matter what, anyone can interfere and conquer or start in that land, and said country can either still attempt to conquer that land or work around it to avoid conflict with another country. And Blazer, if abdullahi were to officially claim the entire world, local populations outside of your country (Cause there are local city-states for the non player controlled lands.) will definitely begin attacking you when they get word.
This also brings me to my next thingy, expanding in land will cost a bit of your military. Reason being, the local populace defending their lands. Depending on how much you expand, there'll be multiple city-states that'll fight against you to stay independent. This is a way to explain why you gain population when expanding in land, because you are pretty much defeating the local militia/military and taking the civilians of the city-state as your own.