Why does that matter. It's a logical fallacy to claim you should be allowed something bad because somebody else does something bad. 
And apartheid absolutely did consider black people subhuman even if it tried to couch it in euphemistic language. Nobody, including the people saying, was in any doubt what it really meant. 
Where do you think the 'obligation' on whites to provide 'paternal guidance' for the development of the homelands came from? Simple : the belief that black people cannot be trusted to rule themselves. Paternalism is blatantly dehumanizing by itself.