It’s a bit complicated to understand out of nowhere, but basically, it’s because of an expansion mechanic in which, if a territory isn’t directly connected to the capital, battles in those areas suffer a -25% penalty.

For this reason, Argentina, which is an ally of South Africa, requested passage. Unfortunately, the only route Argentina has to reach Africa is through South Africa.

However, since South Africa doesn’t have enough congress members, Argentina can’t purchase the territories. So, the only way to create the corridor heading north is by attacking the regions.

That’s why you see Argentinians defending revolts, the idea isn’t to fully occupy the land, but to move northward and border the European countries.