Hinduism is very different from Jainism, Sikhism and Buddhism... For eg. Buddha himself remarked about the Vedas, the main scripture of the Hindus, that they are a 'pathless jungle'... Just because all originated in India does not mean they are same....
At one point in India, there were many religions Shavaism, Brahmanism, vasihnavism who were worshippers of Shiva, Brahma and Vishnu and that is y we have the Puranas where the followers of each god have belittled on insulted teh other gods... read the puranas and u will find out... all are myths....