The average Zuma supporter is poor black. The average Zille supporter is white middle-class, affluent even. Ask Zuma's voters what they think about his (or ANC politicians') frequent travelling and its cost. They may say, 'I don't care as long as I get my social grant and free house, and the country is black-run'. Ask Zille's the same and they may say, 'I don't care as long as I maintain my lifestyle, and the WC is white-run'.
My point, SA politics is about racial/class identity. Just as Zuma's supporters can't see his faults because he's their tribal/class chief, Zille's supporters can't see her faults bec she's their tribal/class leader. The difference is Zille's supporters, being educated and so-called liberal, have no excuse and ought to be better informed than  Zuma's about issues. This is why I'll never convince you with reason about her/DA. (Ditto Zuma/ANC.)
I think Zuma's supporters know a bit more about the vagaries of life than Zille's, and are therefore more genuine.