I was reading Thomas Sankara’s perspective on this recently actually - he made a passing reference to how after the boers where kicked out of Angola lots of opportunistic factions scrambled to seize power, and he gave examples of groups in Angola who claimed to be socialist/marxist but were actually just people looking to enrich themselves at other peoples expense and who had ties to colonial powers.

He was talking about it in a way that he wanted to avoid that happening in his own country, which ended up happening and lead to his death in a coup so man was probably onto something.

I think its just power vaccum and extreme poverty that does this,