Distracted by your tagline:
“If “Majority Rule” was so important in South Africa, why isn’t it that way here?.......”
The political philosophy involved is neo-Bolshevism: a universal democracy where a single party sets the voting agenda. So long as The Party has sole control of the agenda, they’re all for majority rule (knowing the designated outcome); if it’s not, they’ll do absolutely anything to subvert opposition parties until The Party has sole control. That’s why the Left is so utterly freaked out in the USA now: they were certain they’d have that control, but were completely blindsided by Trump whose mandate is to dismantle their system with a chainsaw before they have a chance to resume power.