Google's Explaination on Flagging all the Sites as Malware sites

Google gave official explanation about yesterday's bug where Google flagged all the search results as malware. It wasn't a code push that actually caused the issue, but its a data push. Google maintains all the URL which are considered malware in a file. The URLs in this file are updated both manually and in automated way.
Yesterday the new version of this file was pushed to servers and the file contained '/' as one URL which is like * in the regular expression and so all the sites were listed as malware. Great that team was able to identify this issue soon and revert back the URLs file.
But the question remains is how did '/' get into the URLs list. It can be either manual error or bug in automated malware URL detecting code. Google claims it as a manual error and for that matter any tech company in such a scenario would not admit it as bug in the code. But how can a human whose daily job is to update these URL be unaware that entering '/' would mean all the URLs or is he some disgruntled employee who got pink slip recently?
Now will ecommerce sites like e-bay or amazon sue Google as they may have definitely made losses during this 55 minutes where there site have been shown as malware sites?