As someone who has been to India multiple times and volunteered in Indian shelters, I can tell you that most of the shelters are like this. It was INCREDIBLY difficult to watch animals suffering and receiving little to no medical attention.
That being said, it's very easy to sit here in a first world country and say "how could they do that?" To understand the situation you need to realize that this is an entirely different culture -- almost another world. We might look back at medical practices 150 years ago and say "how barbaric," when, in reality, those people were doing the best they could with what knowledge and resources they had. Most animals in India are considered vermin, so the fact that there are people devoting their lives to trying to save them is a miracle in and of itself.
Also, you need to realize that this is a place where not only animal cruelty is a norm, but there are literally people starving on the streets, people being beaten, women being raped. What seems like an indifference to animal suffering is more of an emotional numbness, almost like a survival strategy.
I agree with everyone that euthanasia is necessary in many cases, but attacking these people is not the way to spur change. The shelter that I worked with was receptive to suggestions, and regards western medicine very highly. These places want to improve the conditions, and hopefully, with guidance from other professionals in the field, they might start to accept different practices.