Which is actually kinda how it responded to Gizmodo's report. Facebook laid out its neutrality in no uncertain terms: "Voting is a core value of democracy and we believe that supporting civic participation is an important contribution we can make to the community. We encourage any and all candidates, groups, and voters to use our platform to share their views on the election and debate the issues. We as a company are neutral -- we have not and will not use our products in a way that attempts to influence how people vote."
... and it already directly influences if people vote
On Election Day, November 2008, Facebook rolled out its "I Voted" widget. It allowed users to proudly let their friends know that they hit the ballot box, and Facebook's activated some variation of this tool every Election Day since. All in the name of civic participation, right? But in at least two instances (that we know of), the widgets were deployed as special research experiments.
In 2010, Facebook secretly tampered with 61 million random users' voting widgets. Its findings, published two years later in the journal Nature, revealed that 20% of users who saw their friends had voted also clicked the "I Voted" button, compared to just 18% of those who didn't see any "I Voted" messages from friends. The most striking discovery? This deviation actually translated into real-world votes -- by consulting voting records after the election, the study's authors determined that the gentle prodding of users actually increased turnout by 340,000, or .14% of the voting population that year. That may sound like an insignificant number, but just remember that a measly 537 votes in Florida are the reason there's no Al Gore portrait hanging in the White House right now.