Here's the part I find interesting. YouTube's content filtering system would have required UMG to upload a copy of the video (or at least have a copy on hand to generate the fingerprint)...
"YouTube has engineered a filtering system enabling rights holders to upload music and videos they own to a “fingerprinting” database."
Even if UMG isn't guilty of abuse of the DMCA takedown system, might they be guilty of copyright infringement for having made an unauthorized copy of the Megavideo and uploading it as their own? I would really like to know more about how YouTube's fingerprinting system works.