In mainland China this mentality gets people divided along very parochial lines. Forget about people from different provinces, there are actually people from neighboring towns with just a few vocabulary differences in their local dialects who get at each other's throats.
在大陸上不要說一省，連不同縣，像方言只有幾個字發音不同的湘潭、湘江人都要械鬥，我說這是中國文化的「窩裡反」。