But these two topics have less than nothing to do with each other ! One is corruption, illegal and terrible (and nobody said otherwise). The other is perfectly legal behaviour - just very evil. 

There is no doubt the NATS were seriously corrupt and DID steal a fortune from the state coffers - especially in the final dying days of their rule - and if you wanted to compare THAT to ANC corruption you'd be having a legitimate debate. 
But this isn't about that - it's about perfectly legal donations to the party - and who made them, and what it says about those people that this was the target of their largesse. Nothing more. 

I don't know if appartheid corruption was similar, greater or lesser than ANC corruption - frankly nobody knows because THAT was not an open society with a free press, most corruption never came to light. You can't measure an unknown. 
But that is a completely seperate topic. The question is rubbish because it's silly.  And "you do worse" is NEVER a defense anyway.