If there is no racism in Islam, why are Syeds not allowed to take Zakaat/Charity?

Islam doesn't believe in racism or superiority of one caste over the other one. But according to majority of the scholars, Syeds (descendants of Prophet S.A.W's family) do not take zakaat because of the following reason : **According to the meaning of one Hadith, Zakat is like the filth taken off the wealth, hence that's why it can't not be given to descendants of Holy Prophet S.A.W's family** **"Charity (Zakah) is not becoming for the family of Muhammad, as it is people's impurities. "** [Sahih Muslim, Book on Zakah, no.1072] JazakAllah