Why ? The answer is very similar to the reason why once loyal Satwant SIngh & Beant Singh turned their guns on PM:- Influenced by civvie freinds/relatives. The talk in villages, gurdwaras, families influence decision.
Well Today Kejriwal seems to be working hard to further lower the bar to win the crown. It seems in India's most literate PM/netas often prove to be .... useless
^ Yep True my elder uncle was in BIA and then IA. Nehru said Army was good for nothing eating away resources, it should be put to work like building roads and dams.