Facebook was once the most nimble company of its generation. The speed at which it adapted to every challenge was legendary. It needed only about a decade to go from a dorm-room start-up to the largest and most influential communications platform in the world.

But it’s been two years since an American presidential campaign in which the company was a primary vector for misinformation and state-sponsored political interference — and Facebook still seems paralyzed over how to respond.

In exchanges with reporters and lawmakers over the past week, its leaders — including Mark Zuckerberg, Facebook’s chief executive — have been comically tripped up by some of the most basic questions the site faces. Mr. Zuckerberg, in an interview with the journalist Kara Swisher that was published Wednesday, argued that Facebook would not ban Holocaust denialism on the site because “there are things that different people get wrong.” He later explained there were many other ways that Holocaust deniers could be penalized by Facebook — yet lucidity remained elusive.

Mr. Zuckerberg’s comments fit a larger pattern. Presented with straightforward queries about real-world harm caused by misinformation on their service, Facebook’s executives express their pain, ask for patience, proclaim their unwavering commitment to political neutrality and insist they are as surprised as anyone that they are even in the position of having to come up with speech rules for billions of people.