According to Osho, disciples betray the Master because many who gather are not true disciples but accidental students or half-hearted seekers; when real practice demands intensity and ego-surrender, they resist, grow frustrated, and rationalize their failure by attacking the Master. This drama recurs through history—same stage, new actors—until a few mature into authentic disciples and devotees.
Most people aren’t ready to really change, so when it gets tough and their ego hurts, they blame the teacher and turn against him.