Those messages were posted on some rando site that doesn't seem to exist anymore - Silicon Alley [no typo] Insider. And I think the lawsuit was mostly them just wanting some of the big Facebook cash rather than actually feeling that Zuckerberg stole anything. Facebook, especially early on, was not a particularly unique nor complex to implement idea. He just hit on some good business ideas by making it feel trendy and elite with the whole university only invite only stuff, ideas Google would go on to copy with Gmail.
In any case though I'm not here to argue that Zuckerberg is some amazing person. But the GP up in this thread wanted to know what was going on Zuckerberg's head, and most people are seemingly incapable of understanding how other's perceive the world without resorting to cartoonish child-like caricatures of villainy. I blame a failing education system that demonizes the past rather than teaching to understand how easy it is to find yourself in the shoes of the villain.
And on that note I think most people would probably end up acting similar to Zuckerberg in his shoes right now. By now he probably loathes social media and its users. But he's also probably unable to give it up simply because it makes billions of dollars, and his other ventures are mostly failures. So he's having kids, playing with politics, and generally living life, while milking his golden goose for all its worth.