Choosing Buddhism over Hinduism does not make one an indegenous. Buddhism also flourished and expanded from India. Let's put religion aside. I do not see any cause to hate Nepali language. Everybody should respect his/her own mother tongue, but if they have some kind of honesty 2nd language should be Nepali, language understood by everyone. But they are in the league to topple Nepali language. As someone said in his comment, if they hate nepali language then do not dare speaking Nepali language in their bhasan and in public.

Lord save my Nepal.