I see that you wrote that in your OP but in your second post you wrote:
”The language on both sides seems to always be so lacking in specifics.
The parents of the adult children talk about having no understanding at all, completely unwarranted accusations, the child is difficult, always has been etc.
The adult children in turn say the parent was abusive and/or narcissistic and/or toxic and/or emotionally immature.
No one ever seems to say exactly what happened to lead to these conclusions.”
My posts were really an answer to that second post, which seemed to be claiming that the adult children aren’t clear about their reasons for their decision, either. I was trying to explain why they wouldn’t share these details with you unless you are someone extremely close to them and why it may take them until quite far into adulthood to realise that they must go NC with their parent for self-preservation, or to protect their own children.
I don’t think it is fair to say that “no one ever seems to say exactly what happened to lead to these conclusions”. The adult children aren’t clear trying to deal with a lot of trauma in the vast majority of such cases and aren’t going to discuss this with people except the very closest people to them and nor should you expect them to do so. The very fact they have cut off contact is an extremely strong indicator that they have very good reasons for doing so; it’s not a decision anybody takes lightly over a trivial disagreement etc.
“The language on both sides is lacking in specifics” is (perhaps unintentionally) conflating very different motivations from the two parties involved: the children dealing with extremely deep, personal and private trauma and not wanting to share their most painful memories with you, which you should not expect. This is why they speak in “vague terms”.
In the case of the parents, the “lack of specifics” comes from denial, obfuscation, and a deliberate attempt to continue to deflect blame onto and scapegoat the child rather than take responsibility for their own behaviour - a continuation of the precise pattern of abuse that abused children are subjected to throughout their childhoods, re-traumatising the now-adult child every time they interact with the parent hence them having to cease contact. These parents are incapable of self-reflection, incapable of genuine remorse, incapable of acknowledging the damage they have done. That is why they want to be vague and pretend the child is “making unfounded accusations” or that this “came out of nowhere” and they are “baffled and have no idea why it happened” even when - as in my mother’s case - it was explained very clearly prior to cutting off contact. She still pretends that she “has no idea why”. It is a pattern repeated again and again.
Per the original post in the thread I can see that your purpose was to get the perspectives of the parents who have been cut off, but this second post (perhaps unintentionally) seemed to conflate the motivations/ language/ behaviours of these parents with those of the adult children who’ve had to do this, which I don’t think is ok.
I hope some of these allegedly “confused” parents will respond to you and provide with their reasoning as to why their children allegedly cut off contact with them randomly and they have “no idea why this happened”. I suspect that if you receive any such responses at all they will all be full of self-righteousness, self-justification, accuse their children of being irrational/ difficult/ mentally ill/ whatever other excuse they can think of to try to deflect any blame and paint themselves as the victim.