Well, to be completely fair MS Labs made it, not the office team, and there is no indication that they made it because it was so hard to use. If that was the case surely then Office would actually ship with Ribbon Hero, instead of having it as an unmaintained experiment you can download from their website if you happen to have heard of it?

IIRC, it was an experiment in gameification and Office and the ribbon was the thing that was new at the time, and it made sense to write it on top of teaching users the new UI.

While we're throwing around anecdotes on how incomprehensible ribbon is, I know plenty of people who are totally fine with it. I don't really use any MS products (and so never encounter it) and don't have an opinion on it, but I think phrases like "no-one likes it, so they shoehorn it into more places" are neither true nor even potentially valid (no one likes it so they use it more because... they're evil? They want you to hate them?)