Would you mind very much googling "Harijan"?
You seem to have latched on to a very strange definition of "racist". Gandhi might have believed during that early period in his life in keeping races separate, which is not surprising given his orthodox upbringing, but he did a very great deal, later, to unite people of all religions and races and motivate them to think of each other as equals, persuading them to literally call each other 'brothers and sisters'.
I cannot accept that that is the same as what is commonly understood as "racist".