It might seem odd that the head of the "Birds of Prey" (even though they were rarely called that) would have some kind of "women make terrible superheroes" idea. But to me, it's more of a "women make terrible Bat-themed superheroes" thing.
Babs sometimes has this big "I was useless as Batgirl" angst going on. Before they knew about Deathstroke's serum, Barbara and Bruce could think "Cass being Batgirl drove her insane." And talking Misfit out of being Batgirl (using Steph as an example) seemed to be "Girls can't play with Batman."
If Barbara appears in "Detective Comics" to talk down to Kate Kane, I'll know I'm on to something.