You can't revoke the citizenship of an Australian if it would leave them stateless.
This is not something Labor or even the LNP can do if they were in government.
There is no doubt these women made a monumentally stupid decision (although some were pressured into it by family, and were only girls themselves). And some may remain a security risk.
The government will need to eventually let them back, it has no choice. What it can do is charge them with whatever crimes they've committed and lock them up here.
The question it's facing now is, does it leave them and their children (who are innocent) in a terrible place where their kids are likely to be radicalised themselves while it dithers with the political pressure, or does it act quickly and provide those children the support services they need?