I remember in the episodes where Pegasus and Galactica reunited (season 2), Colonel Fisk told Tigh about the execution of the previous XO. Then he laughed it off and said it was a joke, but it really happened. I think you guys are are downplaying the ability of people to rationalize following a madman (or madwoman). There are plenty of real-world examples where people follow mad leaders.
Osama bin Ladin
Saddam Hussein
Adolph Hitler
Mussolini
Look at wars America has fought in its history. You will see examples of barbarity that would not normally be countenanced by our people, but because of circumstances in those times, were committeed. Hell, look at the public debate on torture in this country after 9/11 (where less than 3,000 people died). We now debate whether waterboarding is torture or not torture when if you had asked after it became common knowledge that the technique was used on POW's by the Vietnamese, the decision would have been unanimous: waterboarding is torture. Yet now, we debate whether it is torture or 'agressive interrogation'.
Less than 3,000 people dying changed that in our society. In this show, you have less than 2,000 people surviving a holocaust that destroyed over 12 billiion. As far as they know, they are all of humanity that survived, and the only reason they survived was that their leader, Admiral Cain made the right decision at the right time. Who is to say that doubting her future decision is to doubt the quality that kept you alive when over 12 billion others died? There is a mystique to that which gave Helena Cain unparalled power and influence over her subordinates.