Even if Mark Zuckerberg ends up being "wrong" by your definition, why does that mean he lied? It's odd to assume negative intent or that you know what is going on inside other people's heads.
1. Either this reflected a sincere belief by Zuck to build a different kind of product/corporate entity governed more by ethics than by money and power, or
2. This utopian positioning was a calculated recruiting strategy to attract the best and brightest recent grads from Stanford and other elite universities, who were extremely attracted by the idea of getting paid six figures to work on a fascinating product without having to sell our soul, like our friends in finance etc.
Or it could be some combination of those two.
My point is that if the underlying motivation were truly to do good, Facebook would have done something differently over the last 5+ years as the capacity for its product to cause harm became abundantly evident.
Instead, at every crisis/opportunity to fix the underlying issues, Facebook chose to brush problems under the rug in the pursuit of growth.
From my perspective, as someone who drank the Facebook kool-aid more than just about anyone in the early days, this represents a painful betrayal. I feel like one of the "dumb fucks" who trusted Zuckerberg's pitch to me back in the day.
Sure, he might have changed since, but there's nothing wrong with rational speculation. Selfishness and greed are real phenomena in human relations so it would be as foolish to ignore such possibilities as to believe them uncritically.
You're reading a lot into a (admittedly stupid) quip/jab/whatever-you-want-to-call it by a 19 year old.
I don't even disagree with your fundamental assertion here, just that this is incredibly weak evidence.