control-M to insert comment in docs.google.com document does not work
It works in FF. It does not work in Safari even when spoofing as Firefox. Control-M is not an emacs key binding to my knowledge, so I wouldn't expect the text system to eat it.
It would be great to get a reduction, rather than trying to make one from obfuscated code - would it be possible for you to make one?
I don't know how to get the unobfuscated code, no. But I've sent out a query for a reduction.