This is more or less what I've been saying.
>because it is ambiguous //
Ambiguity was my claim initially if you read back.
Clearly you have a handle on DMCA take down notices that I don't. How, if an ambiguity in license isn't sufficient, does the DMCA protect from malicious take down notices. If what you say is true then it appears that one can simply submit a DMCA take down notice and the carrier is always required to remove the content without and need to demonstrate that it is infringing.
Obviously it's fine to remove content that is questionable, within ones ToS, but we're not looking at that.