Casteism is the foundation stone of Hinduism and any other stream is a deviation designed to deflect the onslaught of the modern thought brought in by Islam and Muslims first and colonial rulers.
Casteism is based on the Varna System of Manu Smriti:
Brahmins are born of Brahma's head.
The Kshtriyas, the warrior class, is born of his torso.
The Vaishyas were born of his thighs.
The Shudras were born of his feet.
Hindus call their religion Vedic - religion of the Vedas.
Out of four Vedas the first one is the most respected of all - the Rig Veda.