Haugen repeated over and over again her testimony today that Facebook is full of smart, thoughtful, kind, well-intentioned people, and that she has great empathy for them, even Mark Zuckerberg. Her point is that they have created a system of incentives that are inexorably leading to harmful outcomes. It is not about good and evil people, it is about the incentives. It's exactly as you are saying.
That's why she is not advocating to punish Facebook for being evil, but rather to force Facebook to reveal and permit research so we can understand the system and fix it, because Facebook is too deeply trapped in its own tangle of incentives to fix itself. In this I think she is absolutely correct.