A company gets to decide what business it's in (Facebook and Google have each explored several), what its ethics are, and how these ethics apply. For example, Google is in a substantially similar business, but it is interesting to contrast Facebook's pattern of behavior with Google's.
Google isn't a paragon, and it's alarming (to me) that Google is building a universal panopticon too. But these two companies, despite the similarity in their business models, appear very different with respect not just to how they collect data, what they collect, how much they sell, and what breaches or not-breach breaches have occurred, but also how forthcoming they are about all this, and whether they act like they've got something to hide. Facebook used tricks[1] to run their iPhone app in the background when requested not to, and only backed this out when the new iOS “battery shaming” feature outed them; they uploaded Android call history with text that mislead the user into thinking they were just uploading contacts. Google has made mis-steps and knows a scary amount about us, but I don't recall this kind of systematic boundary-pushing and post-discovery obfuscation and denial.
Or contrast Lyft and Uber.
These differences in behavior aren't from a difference in business models. They are from differences in “corporate DNA”, or culture. Zuckerberg was a teen when he wrote these messages[2], but most people I know don't speak or act like that even at that age. Some people advance to a different moral stage even at the end of, or after, their teen years; it looks from a longer pattern of evidence, only some of it recent, like Zuckerberg and his company may not have done so. Yes, business incentives are a factor, but explanations don't begin and end with “money made me do it”.
[1] http://pxlnv.com/linklog/facebook-background-data/
[2] http://www.businessinsider.com/exclusive-mark-zuckerbergs-se...