Not saying that India is perfect...
But sadistic psychos exist everywhere. I can't find one religious/cultural reference which urges people to rape or pluck someone's eyes out while raping them. You can only blame culture and society so much...
Sure, our lack of respect for women contributes to it, but cases this extreme have a huge internal encouragement. Beyond a point you don't care what society tells, you have to fulfil that blind internal urge. Some people lack empathy and have wild fantasies, a deadly combination.
Some people are just fucked up inside.