Even in the cases where the man has been shit pre-children and it's obvious that it's not an ideal set up, it's still pointless to say "Why on earth did you have children with this man" when she's already pregnant or has had the children.
I don't agree that it's pointless. It makes her think about her part in this and may prevent another pregnancy, accidental or planned.
They really need to get deep down and figure out why they have chosen to be tied to this man.
There was a thread where the posters DH/DP had been blackmailing her sister for nude pictures and stalking her online.
He'd cheated earlier in the relationship and was never great by all accounts...unfortunately she didn't know about the blackmailing until she was pregnant, but now she's in the situation where this horrible man will be in her life for good, even though she's left him..because he has a right to see his child.
Courtship is the time to assess suitability for a long term or life partner. It's the probationary period of a relationship, yet despite failing miserably...having a baby is like giving the poor performing employee a promotion.
I actually say this to managers at work.. you confirmed X in their probation, even though they were crap (I put it more eloquently of course) and now you want to get rid of them and it's a lot more difficult once their past that period.
I may get the "we are where we are Sandy", ...fine...but I still remind them it could happen again, so they need to think why they didnt take the necessary steps in time, when the issues came to light and how much more time/money will cost now.