There's also arrogance on the behalf of Coke's execs. Not only do they think that these beliefs aren't preordained, but they believe that they themselves are doing the ordaining. It seems like they are myopic to the problems of competing in the space Honest Tea is in, and more interested in defending their cash cow.
You don't fill up on salad before a pie eating contest and you don't get into the ring with Coca-Cola on their terms.
The problem here is that Coke has to decide between a unified front and hedging their bets. One way kind of undermines the other.
Not really, and this isn't anything like a prisoners dilema. Coke doesn't need everyone to believe them, or everyone to collude. First and foremost they need their current customers to hear a believable story that HFCS is just fine. "Let the hippies drink that expensive stuff, we've got science on our side". Their customers already want to believe this for various reasons, so they will keep up this front.
I suppose if you grew up on the HFCS version you might be accustomed to it, though.
The sugar versions are smoother.
Coke doesn't need everyone to believe them, what they need is to not lose their very large base so to speak. And for that they need a PR campaign that says what their base already wants to believe. Btw, their base will spread this via word of mouth just as rabidly as you will spread the opposite opinion.