Spammers are scum...
...but who's policing the police here?
I despise spam every bit as much as the next guy. As far as I'm concerned, spammers ought to be dealt with in any way possible, preferably legal but if not that'll do as well.
Problem is, I don't think Spamhaus is run by a wonderful group of people either. Their web pages exude an attitude of "we don't care, we don't have to care and you can't make us care" if you're having a problem caused by their services. They openly state that use of their services is at the discretion of the person using them...and that they are not responsible for any of those uses. They'll also tell you that if you plan to take them to court over something, you will be paying for both parties costs.
(I can fully appreciate how much frivolous crap they probably have to deal with from spammers who don't see eye-to-eye with their filtering efforts, and how they might just be tired of fending off such frivolity. Which might explain but most certainly does not excuse their overall tone.)
Is that a tacit admission that they think someone could take them to court and possibly win? Maybe I'm reading a lot into it (and maybe what I'm seeing isn't there at all) but I very much think so.
I've seen firsthand people who have never sent a spam message a day in their lives have e-mails returned by Spamhaus blocklists. (The machines in question are clean--no malicious software is doing anything.) Some server operators do at least bounce a message back saying that your message was refused by suggestion from a Spamhaus filter, but they don't go out of their way to tell you /why/ that is true and what exactly you should do about it. The advice that's offered by Spamhaus is irritatingly generic, yet their filter must have seen something it did not like.
Come on. It's not like it would be *hard* for the mail server whose ruleset rejected the message to say exactly what the offending rule was and pass a URL leading to somewhere helpful within the Spamhaus site.