Well, that and Babs actually does good when she does the whole "I'm in charge here and your desires are not relevant" thing (Ra's, Helena, Ted's heart condition, even the firing was a net positive), while Ollie's unilateralism inevitably fucks up (here, it's him almost getting himself killed and creating a situation where Cupid can escape, but at least he didn't commit any felonies or break up any families this time).
Also, Dinah seems more willing to call out Babs when she crosses the line, and to do so more productively, than she does Ollie. With the firing, again, she put a lot of effort into showing Babs she was wrong, and got an apology and better treatment out of it. When Babs was like "don't marry Ollie come back to me," Dinah told her off and then brought her around with the "I get it, really, but be my maid of honor anyway" thing. When Ollie misbehaves, though, she either punches him or marries him. It's not really as good a system.