Alan Greenspan (fed chair from 1987-2006) was famous for deliberately confusing forward guidance. Ben Bernanke and Janet Yellen are the historical anomalies for clearly communicating their intent.
https://en.wikipedia.org/wiki/Fedspeak
Quote from Greenspan himself:
> As Fed chairman, every time I expressed a view, I added or subtracted 10 basis points from the credit market. That was not helpful. But I nonetheless had to testify before Congress. On questions that were too market-sensitive to answer, 'no comment' was indeed an answer. And so you construct what we used to call Fed-speak. I would hypothetically think of a little plate in front of my eyes, which was the Washington Post, the following morning's headline, and I would catch myself in the middle of a sentence. Then, instead of just stopping, I would continue on resolving the sentence in some obscure way which made it incomprehensible. But nobody was quite sure I wasn't saying something profound when I wasn't. And that became the so-called Fed-speak which I became an expert on over the years. It's a self-protection mechanism ... when you're in an environment where people are shooting questions at you, and you've got to be very careful about the nuances of what you're going to say and what you don't say.