Honestly, no clue why you're on here.
Not all of the members of estranged parent communities are abusers. Quite a few people show up with stories of losing contact with their children because of drugs, mental illness, cult involvement, abusive sons- and daughters-in-law, or the influence of a vengeful ex. However, most of the people who know why their children are estranged filter away from the group quickly. I don't know where they go, but I suspect they find help in other groups—parents with drug-addicted children find groups about dealing with drug addicts, parents whose children are in the control of an abusive partner find groups about partner abuse. What's left are the people who have no idea why their children left them.
And that, is a vast and waving red flag.