Yes, you're right. But actually, in practice, it and other US companies are the US government's bitches. All to be ridden via proxies known as FISA/FBI/CIA/NSA/PRISM or other acronyms we don't even know yet.
There is some truth to that, but Google is a bitch in every country it operates. For example Canada, UK, Russia and China. In HK (nation that Snowden praised) you actually get censored Google.
If they can compel them to do anything they like, does the technicality of ownership really matter?
I used to trust Google but I don't trust any government, sure as hell not the most megalomaniacal and power hungry one on the entire planet. By extension the rational perspective to take in light of recent revelations is to treat all entities subject to US law as if they were the US government proper. A people who are not permitted to dissent from their government are effectively indistinguishable from it.
Google is a legal entity that is effectively recognized as a person under the USG, not the other way around. Many cities are also incorperated. Are those cities not legally apart and under the influence of the USG since they are incorperated?