Reading the report you provided, I'm not surprised he was charged with murder.

The burglar had got out of the house and the bloke pursued him stabbing him repeatedly in the back. That was clearly not self-defence.

The jury still found him not guilty of murder though!

I wonder if it had been an intruder in the toilet that was killed whether or not there would have been so many calls for OP to have been found guilty of murder - it is not the first time that someone has been mistaken for an intruder in South Africa and 'accidentally' killed, either the intruder or an innocent party.  In all the cases I can find the accused has only ever been found guilty of culpable homicide, (manslaughter).