in ancient india castesim means today's so called professionalism not racism.....kshatriya(warrior tribe), brahmins(preists and scholars), vysya(traders) etc....were given specific work for each section of the society and follow them generations....this is called professionalism not racism.....coming to the dalist or adivasis they refused to come in to mainstream and decided to be in forests, hence in my view they were outcasted because they dont do any specific work in society unlike kshatriya and brahmins....and also i think there must have been a great war in ancient india between hindu caste society and adivasis or dalits , and caste people could have won that war and hence outcasted adivasis...you can attribute that great war to war between devathas and rakshasas in our ancient texts.......this is merely my personal view....right or wrong you decide you decider.....
