Hindus believe that humans are like dogs and they have a breed. So a person who is born in a higher caste is of a better breed than a person born in a lower caste. Numerous genetic studies have found no significant difference amongst Indian castes. The moment an upper caste person realizes that you are a lower caste, you will be made fun of and ridiculed. Caste is also tied to your last name, so when a Hindu person says his full name he is telling his First name and his Caste. Which is why brahmins will be the first ones in a group to say their full name, while dalits will only meekly say their first name. The entire religion and caste system was built to make people feel shameful of their last name. In fact, some last names of lower castes are commonly used as abuses by upper caste.
It is the worst form of discrimination known to man and it's horrible how hindu society openly supports and promotes it. While slavery lasted only for a couple of hundred years, caste system has been going on for millennia. Dalit atrocities are common in India even today and everyday 10s of lower castes dalits are raped, killed , tortured and humiliated just because they were born a lower caste Hindu. Upper caste hindu managers openly look down on lower caste hindus, even in the US , and will discriminate against them. Caste shame is also inbuilt in a lot of Dalit hindus and they themselves feel embarrassed while even saying their full name.
One of the best things I did after coming to this country was to convert to christianity and a few of my dalit hindu friends have done too. Upper caste hindus have no problem seeing a converted christian as their equal, but they would still regard a hindu dalit as inferior. Hinduism has a huge conversion problem even in India, and it is the fastest shrinking religion in the world.