Yeah, people say all manner of shit when their relationships are entering a death spiral -- and that's without the swinging and the cocaine to further pollute the well. I'm not sure that I've ever said anything quite so crass about my kids, but if somebody were to pull something from my past and say 'hey, remember when you said this?' I really wouldn't be that shocked.
Relationships are hard when there are just two people involved. Once you start adding in multiple kids and multiple ex-partners, they get exponentially harder and so much easier to fuck up. At the end of the day, we get measured by the totality of our impact on our children, not by the occasional screw up here or there. If we're judging people's parenting by the latter, nobody would get a pass.