As Ed pointed out, why five only her the questions if it was without purpose?
Potentially there are thousands of “possible” questions and if they let Hillary know what the questions will be that means less time wasted preparing for questions that will not be asked.
I know you will never view my comment rationally but maybe others reading this will give this some consideration so let’s be brutally honest, Hillary had no natural public speaking skills. She was always described as a policy wonk. She was knowledgeable and capable in many ways, but she had no capacity to speak to crowds in a likable way. Hillary had the personality of a dead fish, so her only chance to perform well in debates was she had to stop her campaigning and practice mock debates for sometimes more than a week ahead of time, constantly repeating her talking points and staged commentary over and over and over again so on the night of the debate she could perform.
Being given the questions ahead of time allowed her to practice replying to those questions specifically and poll their paid audience to tweak and adjust her comments.
And anyone who thinks those were the only questions she was given is a fool, everyone was doing all they could to drag that woman over the finish line despite her many flaws.
She spent twice as much money as Trump, had ten times the professional operations set up and had over 20 years of experience in operating a professional campaign, Hillary had all of the media and all of Hollywood and still with all those massive advantages she still lost.
The Russians releasing a few bad emails did not cause Hillary to lose the election, the fact she was the most corrupt professional politician in history and lacking any speaking skills at all is why she lost the election.