And this is coming from someone born in another colonial country called Canada. Canada treated (and still treats) its Indigenous peoples HORRIBLY. The country's policies over several centuries resulted in the subjugation, mistreatment, abuse, and in some cases even complete eradication of Indigenous people and communities.

The difference is that Indigenous peoples in Canada make up less than 5% of the population versus over 80% in South Africa. Imagine being so stupid that you would mistreat, subjugate, and underinvest in people and communities that make up over 80% of your country's population. And you wonder why South Africa is in such poor shape with high crime, high unemployment, bad infrastructure, etc.