I was brought up in the UK to Irish parents and my wider family ( including those in Ireland & the US) was & still is,closely connected. Unlike my parent’s generation, there is no social control, over involvement or religious expectations from any of us towards each other. Yet we all belong together somehow. To the best of my knowledge only one cousin has estranged from their siblings over a property dispute. A brother & sister from the next generation ( both now adults) & who live in Northern Europe (not the UK),have estranged from their Mother. Both of them, despite being raised like the rest of us in the family behave towards, talk about & blame their Mother, very much as you have described the way estranged adult children do in the USA. It seems to be a rite of passage for some families nowadays. The internet is a great tool for good but not always.