Agreed. If I had known at the time that there was a DDoS against Spamhaus, I'd have probably joined in against the self-righteous pricks. Block my home server, will you?
Sure, large and entrenched authorities pose risks. There's not much that can be done about that as long as they're large and entrenched. The best way to ensure their power stays in check is to try to have their customers put pressure on them to clean up their act. And the end-user (you and me) is not their customer. We are customers of the businesses and organizations implementing their block lists. I understand your frustration, and as security professional I have my own beef with Spamhaus ratings, but the answer to that problem lies in comparing their ratings with those of other organizations and a bit of common sense.