We receive such a tremendous amount of unsolicited commercial email (spam) in our In-Box every day, we can certainly understand why some people become "Anti-Spam" crusaders. Since majority is sent with phony return addresses, it is virtually impossible to track them down. While there are ways to find out where it originated, it is usually an exercise in futility, as most come from professional spam houses who own their own servers, and aren't about to shut themselves down.
Most people simply delete clutter, or create filters with their email package to automatically get rid of a lot of it. There are some however, whose primary mission in life is to get rid of all spam on Internet.
Frustrated by their inability to get rid of most of it, they might find a valid email address, and like a hawk seeking its prey, pounce upon offender. They relentlessly pursue their intended victim, and file a complaint with every email address provider they can identify.
Some fanatics seem to take great pleasure in getting someone's domain blocked, or being shutdown by their ISP or email provider. But wait - what if complaint is not valid. We all know how easy it is to forge someone's valid email address, and many spammers do just this. If a complaint is filed against that stolen address, true owner is being unjustly accused. At very least they will have to defend themselves, and worse case they are shut down. This is wrong.
Others obtain software that parses their email, and automatically sends a complaint to every provider found. Now, having a spastic moment, they might do this with a newsletter they subscribe to, and asked to receive. That means that provider of every email address found in newsletter will receive a complaint. This includes authors of articles in newsletter, all advertisers who list an email address, as well as publisher. This action will cause people who are not guilty of spamming significant problems. This is unconscionable.
The typical scenario is that someone subscribes to a newsletter with a free email address, and forwards their email to their permanent email address. They receive publication, decide they don't want it, and try to be removed from distribution list. They are told that they are not subscribed under that address, which is true. Forgetting about fact that it is actually being sent to their free account and being forwarded, their level of frustration increases with every copy received, and they fire off their complaints.
People who make unfounded complaints, like terrorists, are guilty of a crime. No, they don't kill anyone, but they could put legitimate people, who are not spamming, out of business due to their complaints. They are, in point of fact, depriving someone of right to earn a living, and should be legally liable for any damage they cause.