Mainly because if he comes out and is dishonest about pursuing Gruden and says some BS hire was his first choice then he is setting that coach up for failure. Every UT call in show on TV and radio are all Gruden, I would say 75% or more of the fan base thinks this most likely could happen.
Without addressing it, when whomever the coach is, goes 6-6 or 5-7 next year they will not get a pass, seats will be empty again but worse, and we will be talking about this again. At least if it doesn't happen, and either Gruden announces it or the AD addresses it at least whomever they have to settle for has a chance to get fan support. Ignore it and they may have a full on revolt in their hands.
Hart is not traveling, not showing any urgency, and acting like a guy that knows what is about to happen. I remain confident it is Gruden, but equally confident if it ends up not being him it will get addressed by either he, UT, or both very soon.