Do not mix "Zorastrian" and "Parsi". "Indian Zorastrian"s is sometimes used by people not "in the know" to describe "Parsi"s. FWIW, sometimes even people "in the know" would use this lose equality while writing an article for people not "in the know".
You cannot convert into being Parsi. The same way you might be able to convert to Judaism, but you can only be born a Jew.
As such there maybe a misconception online about Indian Zorastrians' opinion on converting to become Zorastrian. Additionally, keep in mind regardless of the debate you'll always see the more passionate opinion publicized rather than the more apathetic opinion (i.e. "I don't care either way if they want to convert. Good for them").