This is all spelled out in the House Weaponization report with copies of emails and everything. Give it a read. I would also like to believe that Zuckerberg did not HAVE to censor information, but he did. So did twitter, google, amazon and every other media source. So the government must have been pretty convincing with their pressure.
Facebook continued to face continued pressure from the Biden Administration to censor content questioning vaccines, including true information, satire, memes, and other lawful content that is constitutionally protected and not violative of Facebook’s content moderation policies. In July 2021, tensions hit a fever pitch, with President Biden publicly accusing Facebook of “killing people.”24 Noting that they had “bigger fish to fry” with the Biden Administration, such as issues related to “data flows,” senior Facebook officials decided in
August 2021 to enact new content moderation policies that would censor more anti-vaccine content.25 An internal August 2021 email states plainly that the decision “stemm[ed] from the continued criticism of our approach from the [Biden] administration.