Google being careful with user data, may be true now. But what happens one day when Google goes bankrupt? And they have to sell all their information about their users at firesale prices.
Yahoo went bankrupt, and sold off its data about their users.
Imagine the treasure trove of information that can be gleamed from every single American's online activities. Imagine all the "innocent" people that can be blackmailed, and have their lives destroyed.
Imagine a company like no other in human history, that is amassing information on every single American, on every single person in the world, and on a scale that has never been done before. Imagine.. Google.
Google needs to be regulated. The public needs to know what they are doing. And we need restrictions on what can be done with that data. If they go bankrupt one day, then they cannot sell it. It must be destroyed. It is too dangerous to be sold off to the highest bidder.