....Is not casteism or varnaism completely different from the most evil practice known as racism? ...., casteism is on account of the unique characteristics like pure Sattvik gunas of brahmins at the top end and the completely tamasic gunas of the lowest castes at the other end?
Brahamists may call it satvik, the racist Whites may call it large skull, doesn't matter, racism and casteism are two sides of the same coin, they both are social constructs and they both are evil.
Take a look at Article 2 of The Universal Declaration of Human Rights which states:
Everyone is entitled to all the rights and freedoms set forth in this Declaration, without distinction of any kind, such as race, colour, sex, language, religion, political or other opinion, national or social origin, property, birth or other status.
What is caste if not birth status?
In Durban, the international community was strongly in favor of including the very term "caste" but the IG stood steadfastly opposed to it. However, the UN Office of the High Commissioner for Human Rights is not bound by these political limitations. In their reports and recommendations they freely use the term "caste" along with race. Here is a sample from their 2002 report.
Strongly reaffirming that discrimination based on “descent” includes discrimination against members of communities based on forms of social stratification such as caste and analogous systems of inherited status which nullify or impair their equal enjoyment of human rights,
Note, the phrase used is "social stratification such as caste"
Another one:
Strongly condemning descent-based discrimination, such as discrimination on the basis of caste and analogous systems of inherited status, as a violation of the Convention,
In any case, I don't want to get distracted into another round of the same old same old. I wish to highlight some quotations from speeches of this great man who passed away, one who was reviled by the rich and powerful when he rotted in jail, but now everyone is falling over each other to fete him and rewrite history, as they do always.