They also like to belong to communities with shared beliefs and values - and that has always been a human need/desire that religions have catered for.  Part of the anomie of a modern pluralist fast changing society is that such "normlessness" and rapid change makes people feel insecure and uncomfortable and so they cling to ancient beliefs and organisations which appear to offer a cosy consensus and a reassuring place in their world.

notes from no w here

A LOT of people don't subscribe to groupthink. Some because their parents vaccinated them against the virus, some because they were naturally immune, some for a variety of reasons.

Humans vary widely in their social relations. Yes, we were originally adapted to small groups. How much can that be modified by atomizing influences in society?

I don't know, but society seems to be limping along. Barely.

Align culture with our nature.