The point of this sort of writing - writing trying to convey factual information - isn't that the reader should notice the words used.The reader should be able to "see through" the words to engage with the story being conveyed - in this case, that of a young lesbian struggling against prejudice and the limitations imposed by society. The words we use in factual writing are like a window, through which we see the landscape of facts - we shouldn't be forced to focus on the glass. It should be invisible.
Using "they" in this way stops that process: the reader notices the language, and so engages less with what is actually being conveyed.
This is why, when we learn a foreign language, we learn about pronounciation. If my pronounciation of (say) Spanish is crap, I may still be able to get by in Spain. But a native Spanish speaker listening to me will have to focus on the words I am using to decipher each one - on the medium - and in doing so will be distracted from the message. By making my listener focus on individual words and how to interpret them I have hampered my ability to engage with people.
It's the same with written language - anything that focuses attention on the words used, as opposed to the message, distracts from the message (obviously poetry and dramatic writing are in a different category - I'm not talking about that).
India's story has not been told well by the Guardian, because of this, which is a shame. Her lived experience has been concealed by the language used, and as a result it has lost some of its force. She has been let down by this clumsy use of language.
Being a female is nothing to be ashamed of India! If we go along with the idea that it is, we're letting the bastards win. Love yourself, take pride in your story, don't hide behind opaque language which conceals who you are.