Writing about your kids is not fundamentally morally objectionable. There’s nuance involved. Parenting is hard and so is being as kid…reading (and writing) thoughtful, high-quality expositions on those topics can be beneficial. It has to be done right.
As for dwelling in the past, learning from experience is the most salient way we learn. If we don’t learn, we don’t grow. It’s odd to imagine disregarding my past or acting as if it were irrelevant. There’s so much growth to be found in reprocessing those experiences, finding your responsibility, and making changes. Writing about them (and reading about others’ experiences) is a valuable way to do that.