In South Indian Hindu temples an adult boy's sacrifices are done i.e., the boy is killed. Should it continue?

In Kaliamma & Mariamma Hindu temples of Tamil Nadu state of India every year a young adult boy is wrapped in a saffron coloured cloth & carried to temples by many & sacrificed i.e., killed for some religious purpose I do not know. Shall such killings continue in a civilized human society ? How is the boy selected ? How do the parents allow ? In a Hindu temple in Karnataka state, once a year on a day after special worship, many ladies come out of the temple & run on the roads of the city in nude, some with ten year old son too. In Yelamma temple of South India , prostitution is allowed & considered good works. There are similar smaller temples nearby. In many temples ladies called devdasis( maid servants of God) are put into prostitution legally. Is that religious in those areas ? I don't know. Can anybody clarify why at all such things happen with human beings in India ?