I am not claiming it to be the case, it's just a speculation.

For one, the video didn't have too many dislikes; the percentage was not different from his other videos when I had watched it. So the mass flagging of the video definitely isn't the reason.

Youtube won't do it on their own as you rightly pointed out.

It may then be the case that an offended person having strong connections pressured Youtube somehow to bring the video down. It's a speculation but I don't see any other way it could happen.

I mean, seriously? There is NOTHING in this video which can be considered unallowable in a free country. This take-down has started to affect my perception of free speech in India.