The problem with free speech comes when it presents a danger, such as shouting "fire" in a crowded theater--an act of speech that has been determined by the supreme court to be illegal.
Those who are speaking out against taking measures to ease climate change, or claiming that the idea is a hoax either have an ulterior political or religious motive or are very misinformed at many levels. Insofar as they are in positions of power, they present a threat to the planet.
Bachmann's position as a US representative, and in your estimation a smart woman, gives her a certain credibility among her fans and constituents. Her speech should be carefully considered and vetted, and checked by her staff for accuracy, lest she inadvertently create a public hazard. Her detractors might even rightfully accuse her of lying when she passes along misinformation.
Recall that you were wrong about your notion that
Harry Reid was against LGBT issues, no doubt because you were misinformed by a source which either didn't bother to confirm their information, or which has an ulterior motive and is attempting to sway public opinion. You acted on this incorrect information by passing it along on a popular web site, JREF. Do you now want to retract your post? If not you are open to being accused of lying. You see?