You are mistaking speech, with it's communication of concepts, ideas, truths and expresion, with slander and fraud. Speech is a right. Slander and fraud are violations of rights. Govm'ts only justification is to protect rights. The 1st Amend protects speech, not slander and fraud.
"There are no absolute rights."
Sure their are. Here's a short listing: Life and the individual sovereignty of will that derive from it, self defense and the right to mount an effective defense, (see free speech and the 2nd Amend.) The right to religeous freedom, including expression and exercise thereof.