A webmaster posted an issue in the Google Webmaster Help forums with the Google URL Removal tool.
In short, the site he is working on was hacked. He is using the tool to manually remove the hacked pages from Google, one by one. But for some reason, one of the URLs he entered triggered not just one page to be removed but all.
He asked:
Why on earth would the Google Webmaster Tool developers think that url parameters were irrelevant, and how do we get this fixed?
Here is a screen shot:
John Mueller from Google responded in the thread saying:
Thanks for reporting this, Michael (and thanks for escalating, Grace!). I'll check with the engineering team to see what's happening here. It's great to see you help clean up this kind of hacked content!
It might be the configuration of the hack, confusing Google? I am unsure.
Forum discussion at Google Webmaster Help.