The confusion arised when an answer was given to this post. One would typically associate believing in a religion as believing in the gods of a religion, but, it seems so there are sects of Hinduism who are atheistic. If this is the case, what is the criteria which must be fulfilled for one to call themself Hindu?
Please read my answer here: https://thespiritualhindu.com/who-is-a-hindu/?
Briefly, Shashi Tharoor is incorrect if he said there are 'no binding requirements.' Indeed, Hinduism has a very strict epistemology across all Darshanas. One can call yourself anything you want, but if one is a Hindu in the indigenous sense, one must be a Dharmic creature. Religion is not part of the indigenous belief system; Dharma is.