Of course you'd want the 'useful info from trustworthy source', but that's not a search engine's job (to decide what's 'good' or 'bad' info), is it? Google finds it, you decide what it means.
Successful businesses deliver something that people want. Google and others get this, you don't. You're looking at the scenario from the point of view of an employee who does only what he's obligated to do and nothing more.
Incidentally, I personally *DO* occasionally rely on Google to identify a site's legitimacy even now. In situations where a project/organization/company's domain name is not obvious ( e.g. mplayer), googling their name will generally show the top result as the actual, legit site, instead of perhaps a scammer selling a fake.