The opressed classes, the shudras were not humiliated by ghaznis or ghoris my friend. they were trounced humiliated by the upper castes. the devision of the hindu society was not made by aurangzeb. It was manu (manusmiriti) who categorized brahmins, kshatriyas, vaishnavas and shudras. Because of the atrocities of the upper castes, most of them had to convert to other religions. Now you cry? shameless You have to blame yourself.
