> First of all he's not wrong - anyone with a FB account (including myself) is an idiot for trusting them

First of all, many intelligent people got FB accounts in the early days because they didn't know / understand the privacy implications. Eg, some of them surely were college students who went on to become neurosurgeons, astronomers, doctors, etc. They acted on a reasonable heuristic - "this web site looks legit, people I know are using it, there appear to be social benefits, and I live in a country where rule of law is generally enforced, so it's probably safe enough." So they were not dumb categorically, even if their decision in this case turned out to be (arguably) dumb.

Second, for you to call the users idiots for trusting FB is one thing. For Zuckerberg to call them idiots for trusting him is different. A scammer probably thinks of his victims as idiots, whereas their friends think of them as regular people who got tricked. The quote sounds like he meant "because of course I'm going to abuse that trust."

And in context (according to https://en.wikiquote.org/wiki/Mark_Zuckerberg), that appears to be exactly what he meant, treating users' information as his own possession.

> Zuck: Yeah so if you ever need info about anyone at Harvard > Zuck: Just ask > Zuck: I have over 4,000 emails, pictures, addresses, SNS > [Redacted Friend's Name]: What? How'd you manage that one? > Zuck: People just submitted it. > Zuck: I don't know why. > Zuck: They "trust me" > Zuck: Dumb f---s

So this quote is brought up not because it shows his insightful analysis of the fact that generally speaking, people should not trust online services, but because it seems to show his own intent, from the beginning, to take advantage of FB users and blame them for trusting him in the first place.