Most of the private data Google collects about individuals is provided freely by the people. (Perhaps not all, and maybe that should change, but the point still stands.) Google and others use it to target advertising. The government uses it to monitor people for perceived wrongdoing and imprison them. There's a difference.
Privacy isn't necessarily about keeping everything private from everyone, it's also about choosing who you reveal information to. It is perfectly legitimate to be willing to reveal private information to Google, but wishing to prevent the government from being able to warrantlessly scoop it up as well.
