I love how all these companies who had no qualms about collecting our personal data and slinging it to anyone with a paycheck have all of a sudden become Constitutional warriors.
Google does not sell user data, except in the form of aggregated, anonymized statistics. Google's major profits are made by using user data internally to target ads, but without giving user data to advertisers. It all stays in-house -- and Google is very careful about keeping it secure against intrusions, leaks and even access by employees.
This is why the government request stories are so damaging to Google.
Google's "deal" with its users is that Google collects and uses information from searches, e-mails, etc., in order to figure out what ads to show the users. The users get high-quality free services, including "better" ads -- hardly anyone likes ads, but most everyone would prefer that if they have to see ads that the ads be for products which interest them. Advertisers get cost-effective advertising, since they only pay when someone actually clicks their ad, which means they only pay for good leads. Google, of course, gets money from the advertisers. The more information Google has about users, the better it can target the ads, which means the more ads are clicked.
As long as Google does a good job of ensuring that user data is only used in that way, most people consider it to be a reasonable trade. That trade depends on Google doing a good job of keeping user data tightly controlled, and I think most people have the perception that Google can and does do a good job of keeping their private data private. But if some external entity has carte blanche to rummage through the data at will, then the balance of value changes, because the risk to users is greater.
We grant government permission to do that sort of rummaging for good reasons, but generally don't give carte blanche. Government should only be able to request specific information about specific individuals when it has proven to a skeptical magistrate that it has good reason. That's the theory. But the telcos have, apparently, been giving free rein to federal agencies, and now we have this allegation that Google does, too. Or that government has been legally compelling Google to provide open access, which amounts to the same thing.
Google wants to be able to prove that it has not been providing open access, but government gag orders prevent that. This means that those government gag orders are materially damaging Google's business, because it doesn't matter how good Google is at safeguarding the user data it possesses, if everyone figures that government agencies have wide-open backdoors.
(Disclaimer: I work for Google. I don't, however, speak for Google and they don't speak for me.)