I'm not a lawyer and this isn't legal advice. I used to work in the security and abuse department of a major hosting company. Let me shed just a little light on the DMCA for those of you who don't know. Consult a lawyer for more details or about any particular case.
The DMCA requires that the recipient of the notice at a safe harbor host notify the party responsible for making the content available on the host. Then that party has a certain amount of time to file a counter notice saying the takedown request is erroneous and why.
Faking the takedown is punishable. Faking the counter-notice is punishable. Either party may make some mistake in that process, though.
The party that has no say is the safe harbor host. If you get a takedown notice and get no counter-notice you must take down the content permanently to keep your safe harbor rights. Most hosts take things down proactively and will restore them after counter-notice has been filed. This absolves them of legal liability from either side under the DMCA.
Google's doing what I understand the law says they must. Paramount / Viacom may have made an error or may have some hatred toward Linux, Ubuntu, Canonical, Shuttleworth, the FSF, or what have you. Google's doing what they are obligated to do in order to keep themselves out of the middle of any litigation over it.