You really need to stop thinking about what is said, what isn't said, and the why's of these being said publicly. They make no difference to the actual dealing.
If Barca want to sell, and Fabregas wants to come, we negotiate with Barca no matter what is said in public. Problem is that none of that looks like it's the truth, so Moyes saying anything in public makes no difference with regards to obtaining players.
You're thinking is all geared up to what we look like in public. Barca's board don't give a shit about that and confirming it publicly/not saying anything makes no odds when a rival board member is sitting at a table with them to thrash out a deal.