Sectarianism is bigotry, discrimination or hatred arising from attaching importance to perceived differences between subdivisions within a group, such as between different denominations of a religion or the factions of a political movement. help !!
Sectarians often havebroadly the same underlying beliefs (or roots thereof) as other groups they dislike, like Catholics and Protestant, or the Stalinist denouncing of Trotskyist movements, and libertarian socialists.
The Monty Python film The Life of Brian has a well-known joke in which various Judean groups
The Monty Python film The Life of Brian has a well-known joke in which various Judean groups, who to an outsider are indistinguishable, are more concerned with in-fighting than with their nominal aim of opposing Roman rule.
Sectarianism is descrimination of people who are of the same religion as yourself but a different faction,such as Catholic and Church of England,Shia and Sunni Muslims etc.