Remorse, I think this plays the biggest role of why Masipa ended up with her verdict.
I remember reading an article about the case where Masipa handed down 252 years sentence. She said that the perpetrator has shown no sign of remorse as part of the reasons of why she handed out the sentence.
Everything Oscar did on the stand is to prove how remorseful he was. He started off by apologizing to the Steenkamp's family. Then proceed to cry, wail, puke, while looking absolutely miserable. Masipa bought his performance. She believes Oscar is remorseful, thus losing Reeva is more than a punishment for him. That's why she doesn't want to punish him "twice".
It's also easier to feel empathy towards Oscar where all the focus had been on him. We were spood fed with so many information about Oscar, but very few were about Reeva. If I didn't read any articles about Reeva online, I would have known very little about her just from the trial. The entire trial was to make Oscar the ultimate victim, not Reeva. Oscar's family also helped in the theatrics, crying, praying, hugging - they were all to emphasis their victimize status. In the end of the day, Reeva was just an unfortunate person. The true victim here is Oscar.
Masipa has judged the entire case solely based on her emotions. Evidence weights very little for her. I have to agree that she should have stayed as a Social Worker. A Judge should not be swayed by their emotion, they should be looking at all the evidence and analyze them, not thrown them all away in favor for the testimony of the poor crying man right in front of her.
Good post, especially the last para BBM. I'm absolutely astonished that she could've been taken in by a killer who put on the theatrics that OP did .. of course that's what murderers do, it's exactly what they do in order to try and convince people of their innocence! I simply cannot believe that a judge would be so stupid as not to know this .. and I think it's because she has, in the past, dealt with a different type of domestic violence .. ones where it is just plain and simple violence, without the manipulation, etc, so therefore she doesn't understand the mindset of someone like OP who is able to lie at the drop of a hat, or put on the 'showing remorse' theatrics (when actually, what it is is a transfer of emotions on the part of OP .. i.e. he is upset about his own future, but is able to transfer those emotions to be able to make them look as though he is upset that he killed Reeva). I think that SA is very behind in not understanding the psychology behind domestic abuse and violence, people are only just really beginning to understand it here in the UK, but we seem to be a lot further ahead it has to be said!