Of course everything you've said is true. Nobody critical of divorce is saying, "it's the literal divorce that's bad for kids and as long as you just stay together and change none of the behaviors that lead to divorce, then that's better than getting a divorce."

But on the other hand, upper-middle-class Hacker Newsers who got divorced because they were "unfulfilled" probably shouldn't point to extreme cases of abuse and neglect to justify their decision, either.

All things being equal, people in this latter category should try to work it out. (Nobody disputes that there are extreme environments for which divorce is the only option.)

Finally, as always, we are talking about averages. Sociology doesn't have a proof-by-counterexample. If I say, "poverty leads to worse outcomes for kids" it's not a legitimate response to say, "there are some wealthy kids who do bad and some poor kids who do well, so you're wrong."

We're always talking about averages.

[0] argues that there is a differential impact of divorce on the children depending on the type of family they come from. You can divide families into two broad groups – high-functioning and low-functioning. High-functioning families, the parents may be unhappy, but they try hard to hide their unhappiness from their children, and the children may have no idea the parents have any marital issues. Low-functioning families, the children are very-well aware of their parents' unhappiness, they witness constant fighting, even abuse and domestic violence. Children from low-functioning families often experience their parents' divorce as a relief, and can even benefit from it. Children from high-functioning families, their experience of their parents' divorce is often much more negative.

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6462058/