The key quote in this changing of loyalties comes when Eisenberg responds to his lawyer’s suggestion that he must really hate the pair of establishment types who are suing him for all he’s worth. His response describes in a nutshell the major conflict running throughout the film:
"I don’t hate anybody. The “Winklevii” aren’t suing me for intellectual property theft. They’re suing me because for the first time in their lives, things didn’t go exactly the way they were supposed to for them."
The viewer has moved from a point where Zuckerberg is the “asshole” to a place where she is asked to sympathize with Zuckerberg against the seemingly invincible connections, wealth, success, and arrogance of the Winklevoss twins. Moreover, you’re asked to do so while dealing with the fact that Zuckerberg is still the same guy who acted like a child in the film’s first exchange.
Brian Dijkema at the Cardus Blog