Free speach? What the hell does that mean? Does anyone know?

All the time you are hearing about people being kicked out of these type of appearances by politicians because they ask questions that could potentially harm their approval ratings, or open a can of worms that once opened, all hell breaks loose. I believe that the speaker tells their agents what questions that they will and will not answer before even entering the platform.
As citizens, we responsible for electing the best candidate for our most important seat in government, the President. We should have the opportunity to ask any question to a candidate pertaining to their duties and their responsibility as our future President of the United States.