I think in many cases it is innocent curiosity, but then we are surrounded by a culture obsessed with conspiracy, so the idea grows that if they (whoever they are) won't tell me what's going on, they must be hiding something. That is the point where some people take things way too far and start making a fuss on FB or whatnot.
I think it has always happened to some degree. We both grew up with the idea of the old women gossips in the neighborhood who just stare out their windows all day and milk everyone they meet for info on everything that is happening with everyone. There were entire episodes of those old 50s and 60s sitcoms that revolved around the local gossip lady trying to demand info that she didn't need to know and then making a fuss about it. Kind of a Proto-Karen.
So that is to say, I think the internet has just amplified something that was already with us.
That said, yeah it is annoying! I deal with it too (and wish I didn't have to).