The only penalty spammers suffer is losing their throw-away accounts, and having to get more. I'm baffled that anyone thinks there's any debate over whether e-mail spammers should stop. The only question is whether they will destroy e-mail first, like any parasite that kills its host only to then immediately die itself. If they are, then so was the old USSR, for running powerful jamming transmitters intended to make shortwave radio unusable. The effects are similar.
Freedom of speech applies to consenting adults.
It doesn't mean anyone has the right to paste their ad over someone else's billboard without the permission of the owner. Or that they can scratch their message onto the side of your new car. Or that they can broadcast it from a loudspeaker outside your bedroom window at 3 am and refuse to stop. Nor does it matter whether it's a commercial message or not. It does mean that two people who WANT to communicate can do so, no matter what the subject matter.