It's common enough that you can call it Indian head wobble.

Not all Americans are fat, you can still talk about the American obesity problem even if a few of the states are fitter than the European average.

People talk about American accent, but a Texan, a Californian and a New Yorker (just to pick 3 of many examples) will sound very distinct.

People talk about beer tasting German, but it's very distinct between Bavaria and Cologne.

Not talking about the Indian head wobble is just unnecessary hair splitting. It's an interesting phenomenon which is spread widely enough in India and throughout the Indian diaspora that you can call it that.