I think he refers to how Ibadi is supposed to no longer be a heresy after SoA (it's a new Muslim branch with its own heresies). It's still a heresy for me, but I always assumed that this would only change with SoA installed, and since I haven't gotten that (or RoI) yet, I never fretted about it.
Likewise, without SoA I can't get heresies to "overcome" the parent religion as it seems can happen (took over Catholicism as Fraticcelli, still a heresy).