Although not a real friendly response, I think Google's attitude was the right one. If it was so easy to just send an email to Google to get a site removed from the SERPs, then they would be bombed by emails from webmasters accusing other webmasters of copyright violations and asking for immediate removal of those sites from the index. You can always file a DMCA complaint, which Google has to act on, but that requires a document with your signature. That will block at least 95% of all bogus complaints.
My experience until now is, that the only reason for a removal of a site from the SERPs is a clear violation of the webmaster rules. Cloaking sites and those that violated Google copyrights/trademarks were the fastest to disappear.
Bad linking strategies is mentioned in the webmaster rules and maybe they turned a control knob a little higher resulting in sudden removal of several sites.