>>Why has the culture become such that this seems to be everyone's business?

Mostly because any movement, when it becomes a little bigger gets crowded by gold diggers. And from there on its just people's selfish motives at play.

Politics, and even office politics is all about this.

>>In India, where I live, we constantly fight against a culture that is in favor of moral policing.

Indian here, I entirely agree. Entitlement in the India society, especially related to social influence is just too much to bear at times.