Stallman: Ubuntu Spyware: What to Do?

As stated in the article the problem isn't that the feature exists or that you can't disable it (you can) it's that it's the default and any users who aren't savvy about it could leak information unintentionally. It would be better if the feature was opt-in or the result of explicit user action that was clear you were doing a network search and not a local search. The fact that Canonical proxies and anonymizes the requests somewhat may help but this requires an ongoing trust relationship that they won't misuse the data they gather that wouldn't be necessary if the feature was opt-in or explicit.