Discrimination on basis of caste is a big crime in India, be it known to them who are ignorant. Chief minister of India’s most populous state and one of the most powerful woman in India is from Dalit class. But I too dont rule out isolated incidents.
Now lets talk of slavery. Can someone come ahead and tell me whether slavery is a crime in Islamic state unlike rest of the world? I think no, keeping slaves and even sex slaves is very much lawful in any true Islamic state.
My above comment should not be taken as anti Islamic but as a truth unless someone can come ahead and prove me wrong quoting from holy scriptures.