First amendment absolutists like to cite the text of that amendment and then smugly declare the case decided, for instance:
"Congress shall make no law abridging the freedom of speech, or of the press. Now get over it."
But have these people thought about what "abridge" means?
"abridge: to reduce in scope, extent, etc.; shorten"
So, this amendment does not in the least say that the freedom of speech is absolute; instead, it says that, whatever that freedom is, Congress may not reduce it.
And if you read a little history it is clear that no Founder thought that right was anything like absolute. Not a single one of them thought that, for instance, laws banning pornography were unconstitutional.
It is one thing to argue that they were wrong, and that the freedom of speech should be considered absolute. It is quite another to make the blatantly false historical claim that the Founders did think it was absolute.