> I believe Facebook has a history that shows it repeatedly failing to be trustworthy

You can say that again. Here's a great list from over the years: http://pleasedeletefacebook.com

I don't think there's a rigid bar to judge them by, though - nobody else has had this much data in one place before. There are best practices and things that one might deem "sensible" or "fair" but they're ultimately still trying to figure out just what to do with all this data.

Put it a different way - do you think anyone who works at Facebook would want people to think the company isn't trustworthy? I'd suggest not as it does nothing but harm the company. The decisions are likely made with the best intentions in mind, but to err is human and I don't think that Facebook have all the answers.