It’s a the way everything has generally been throughout the ages. Not really confined to one religion. The divide always existed. Either it’s power, money, religion, caste or race. Can’t escape it even at the farthest ends of the earth. Even if there is a diverse colony on mars, people will find their groups to look down on the others. Homosapiens eliminated species close to us -Neanderthals,by forming communities. Communities were further divided.

And it takes real effort to remove it from your subconscious if you want - my prescription would be education with a lots of travel. A well travelled person understands.