And the prosecution can simply point to the thousands of laws which infringe on the freedom of speech, such as requiring licenses for almost all aspects of print for sale, broadcast, and permits to assemble. There are also laws against libel, and hate language laws are cropping up all over. I could go on, but I would suggest the defense needs a tad better argument than that.
Permits to assemble can only be used for deconfliction, they cannot be denied simply because the permit granter doesn't like the assemblage or he opinions to be expressed. Time, place and manner can be regulated, but not content. They can refuse a parade permit at rush hour, or because someone else already has a permit for that time and place. No permit is required if the assembling takes place on private property, although if the owner or lessor of the property doesn't give permission then trespassing charges can be brought.