An interesting problem -- is Google forced by the EU ruling to de-list anything related to the de-listing of a page?

Not simply for commenting on the de-listing, but if the page is republishing information that's considered a violation of privacy in the EU, it's still a violation of privacy. This would be clearest in the case of e.g. compromising pictures of high-school kids or other such non-public figures. If you started a site reposting those pictures after Google delists the original sites that published them, obviously your site would also be subject to delisting.

This is going to lead to super- and hyper-injunction levels of stupid.