but, by defintion I must therefore sue Netscape/AOL tomorrow morning as its DMoz entry for many of my sites is plainly plagiarism. And often done without my permission.
Big difference to the previous point. You can contact Netscape/AOL (without suing them) and have your entry removed. Try doing either of those things and having success with a thief.
Back to the OP, if G has created the opportunity, then why not just leave it and let G sort it out. Reporting a site is like holding back the tide.
If you don't find the information you need, go and use a different search engine. Google will soon pick up on that if enough people take that step.
If it really upsets you to see poor quality or copied MFA sites, feel free to report it. On the ads, you'll find the text "Ads by Goooooogle" Click on that to make your comments. Let the owner of the original material know. I applaud you if you do.