Now I realized that Google made a mistake: the DMCA complaint was related to web search, not Blogger. Inspection 12 actually requested to "to have this URL and others like it to be excluded from google search results for the name 'Alden Howell'".
My post didn't include that name and a search for 'Alden Howell' didn't return that blog post. The obvious reponse would be that there's nothing to remove from search results. Instead, Google decided to reset the post to "draft" status and tell me to "edit the post to remove the offending content and republish, at which point the post in question will be visible to your readers again."
As I've explained in the previous posts, there's no offending content to remove: my post had nothing to do with Inspection 12 and it didn't include their lyrics. The post only linked to a Greasemonkey script that displayed music lyrics next to the YouTube player. That script obtained lyrics from sites that now license content from Gracenote and some of those sites actually allow third-party software to use the lyrics. Ironically, the script no longer works.
Just in case anyone is wondering, the obsolete post from 2008 is not the main issue, I'm worried that it's too easy to remove web content. Google says that "if it is brought to our attention that you have republished the post without removing the content/link in question, then we will delete your post and count it as a violation on your account. Repeated violations to our Terms of Service may result in further remedial action taken against your Blogger account including deleting your blog and/or terminating your account. DMCA notices concerning content on your blog may also result in action taken against any associated AdSense accounts."
Update: I found this information from the Google Transparency Report. "From time to time, the Search team may receive copyright removal requests for search results that link to other Google products like Blogger or YouTube. In these cases, we forward these requests to the appropriate teams to evaluate the allegedly infringing material."
I've contacted Inspection 12 and they say "that must have been submitted in error. not fully understanding the DMCA notice. our intent wasn't to post on a blog or complaints about a blog. it was to submit a complaint to google about websites that are posting lyrical content that is falsely described as Inspection 12 lyrics in order to sell ringtones." How to fix this?
Here are the other sites affected by a similar requests (all of them are lyrics sites). 18 of the 20 pages have been removed by Google from search results.
Update: happy end.