Pranoy Roy and her sister Arundati Roy both are Christians. Why do you think they have visceral hatred towards Hindus. Be careful of all the recently converted folks, they are the most virulent of the lot because most of these conversions are political and have been done by filling them with hate.
I would also say that their leftist leaning is just a facade. If you are a leftist then it is easier to go against BJP and other nationalist forces. Do they work for outside agency--I dont know. Western power brokers hate nationalists of all hues. Pranoy Roy, Pritish Nandi do this job of countering BJP nationalists with aplomb under the cover of left. They have done their share to keep India divided, weak and helpless.