Yes, it was right of Periyar to criticize Hindu scriptures to eliminate the caste system. This is because Hindu scriptures like the Manusmriti justify the caste system on grounds of religion. Such justification exerts a powerful hold on the people which leads to the perpetuation of the caste system. People support the caste system due to such scriptures. The only way to break the hold of scriptures on people is to criticize such scriptures. Hence, Periyar was right to criticize the scriptures.