Keep in mind that freedon of speech says that you can stand in the park on a soapbox and shout.
It does NOT say that passers-by are forced to stand there and listen to you until you run out of voice. They can walk away any time they want to. It also does not say that the local newspaper is required to take down everything you say and print it on the front page for all their readers. (But freeedom of the press says that they can, and you can't sue them for copyright infringement or much of anything else for doing so, even though people and organizations now try that.) Whether any organization has an obligation to convey the voice in the park to all of its customers, or even a selection of them, is an interesting question. By and large, organiizations in the US have the rights of individuals, and that includes the right to walk away and stop listening. The major possible exception would be a "common carrier", which cannot disconnect a call because they don't like what is being said. But ISPs are NOT common carriers. So even if the spammer is addressing spam to specific individuals, the ISPs, not being common carriers, do not have an obligation to deliver the spam.
