Yeah I did think of that as I was writing this response, but there is a difference though. As I note in the Catalonia example the sentiment is not tribalism as people generally want to retain relations with the foreign neighbors post independence (e.g. I bet most Scots want to rejoin EU post independence).

I bet even most people voting for Brexit didn’t want this hard “we are on our own, and we don’t care for nobody” type Brexit as you would expect if tribalism prevailed (as evident that most people even in favor of hard no deal Brexit still favor CANZUK).