Another thing they have in common is having children. A group of bad people having something in common doesn't tell us anything about the thing. Obviously the motivation in their case might be a bit suspect but nuclear families with strong parental authority are nonetheless a good model for families. I'd argue an extended family is probably a little bit better, but nuclear isn't bad.

Same goes for cults, calling something a cult doesn't automatically mean it is an organisation dedicated to destroying itself. Some cults are organised by people who ultimately want their community to be successful and hold extremely worthwhile values. Too much authoritarianism will be a disaster but nuclear families are a good compromise position where there is just a dash of authority in the small.