People behind NoSQL movement understand SQL better, than any people glorifying SQL here. In fact, I think this is a testament of how poorly most people actually understand SQL, they can't even see basic on the surface problems with it.

All I heard from NoSQL proponents was that "relational databases don't scale". These same people were usually dealing with data sets that would fit easily onto a single server.

No, I'm pretty sure you only heard it from your fellow RDBMS friends. I have never argued for scale myself, but plenty of times tried to debunk this exact stereotype.

No.

I think there are people who went with NoSQL because it fit their specific needs better than a regular RDBMS, and people who went NoSQL because they found it easier to work with than a RDBMS (at first).

The latter group often didn't want to learn SQL and went with NoSQL's as a shortcut, not because they had an intimate understanding of the tradeoffs between the approaches and decided NoSQL was the better option.

There was the third group of resume driven developers who bought into the MongoDB hype around 6 or 7 years ago, which probably overlapped with the second group a bit.