This is just another feature of tribal thinking. For various reasons, people are no longer able to differentiate, so that at almost all levels it is now all about “us” versus “them”. And how did that come about? Those who have power and money make the rules and distract us from the real causes of people’s problems by dividing us. And most people seem to swallow this unreservedly. If you don’t believe me, just read the comments here in this thread alone.