Religious people getting angry at atheists criticizing religion are like arsonists getting angry at the fire brigade for putting out the fires they started. Like seriously. Look at the argument: "Why do you have to do this thing? Why can't you do that thing?"
In India particularly, this response is common. Partly because of your familiar old denialism of reality. And partly because Hinduism tries so desperately to absorb atheism into itself (like everything else). The goal is to turn atheism into just another Hindu thing so that it can't be opposed to Hindu dogma and cultural practices.
And of course, when Indian atheists do still do what any vocal atheist should do to the dominant strain of religiosity around them, religious nostrils start flaring. "This isn't what atheism is," they say. "Atheists should only talk about pleasant things like science awareness and how ancient India has always been home to futuristic science. That's what a good "Hindu Atheist" is supposed to do."
This appropriation of atheism by Hindus has gone on for far too long and is just another example of Brahminical assimilation of opposing viewpoints. They did it to the Buddha by declaring him another avatar of Vishnu, they did it to Jagannath by declaring him part of the Vaishnavite mythos. Now they're doing it to atheism. This culture of abduction is an old game.