The article ‘Mahayana/Theravada III: The Great Schism’ the author Bhikkhu Cintita states that the story of the “Great Buddhist Schism” that occurred during the Second Buddhist Council, approximately 350 BC, is fictional with no evidence to actually support the story.
The author cites that Chinese Buddhist pilgrims to India, during the 4th to 6th centuries, found that both Mahayana and Theravada monks lived together in harmony in the same monasteries. As Buddhism died out in India, the Chinese pilgrimages stopped. The divide in terrain, language and physical geography simply allowed the regional religions to develop on their own over the centuries.
In this, he states that there never was a ‘Schism’, rather just different preferences: as in how one roommate reads mysteries and another reads science fiction.
The pañcānantarya list ‘creating a schism’ as a major crime, an offense that so grave that those monks who were convicted of such would be forcibly disrobed. Yet, to believe there is a schism when there is no evidence and no victims, (injured parties) then maybe also a crime too.
Modern Zen tends to get into this ‘Karate Club’ mentality, in where the Lineages boast of their teachers, their holdings, and the mystical powers of the founders. This sort of braggadocious talk is often performed by weak-minded practitioners who cannot see the merits of the teachings, so therefore embellish Lineage as a means to attract new students and supporters.
As Buddhism flourished in the different geographies and regions, isolated from one and other, different rules for monks where created – often out of necessity and sometimes imposed externally by kings and emperors. Regional politics does have its play in the religious lives of monks.
Even today, external forces intrude into the Buddhist sects to impose their changes and those misguided accept the externally imposed changes, if not out of fear then out of greed – in hopes of getting something from the external forces.