Blumenthal brought up Twitter's decision to suspend former White House Chief of Staff Steve Bannon's account after he shared a video from his online show during which he called for the firing of FBI Director Christopher Wray and Dr. Anthony Fauci and suggested he'd like to "put the heads on pikes."
He then asked Facebook CEO Mark Zuckerberg why Facebook did not take the same action against Bannon's account.
"You removed the video, Mr. Zuckerberg, but on Thursday, you reportedly told Facebook employees that Bannon had not violated enough policies that he should be banned from Facebook," Blumenthal said. "My question to you: How many times is Steve Bannon allowed to call for the murder of government officials before Facebook suspends his account?"
Zuckerberg said the video violated Facebook's policies, which is why the platform removed it, but added that "a content violation does not automatically mean ... your account gets taken down, and the number of strikes varies depending on ... the type of offense."
Blumenthal responded by saying he is "very concerned that" Facebook "seems to have a record of making accommodations and caving to conservative pressure."
He also suggested Big Tech companies should be broken up, mentioning Facebook's acquisitions of Instagram and WhatsApp, specifically.
"I have urged, in fact, a break-up of tech giants. Because they've misused their bigness and power," the Connecticut senator said. "Breaking off, for example, WhatsApp and Instagram; rigorous privacy protection because consumers should have control over their own data and, indeed, Section 230 reform."
Sen. Dianne Feinstein, D-Calif., also suggested Facebook can do more to censor certain content, such as disputed claims from President Trump.
Feinstein brought up Trump's tweets suggesting voter fraud took place during the 2020 election and asked Dorsey if Twitter's label that reads, "This claim is disputed," goes "far enough to prevent the tweet's harms when the tweet is still visible and not accurate." Dorsey said the label is linked to more information.
Some Democrats have criticized Facebook for being a "right-wing echo chamber" with a "conservative bias" due to the popularity of conservative commentators on the platform including Dan Bongino, Ben Shapiro and David Harris Jr., according to Politico. Republicans have argued that Facebook and Twitter alike appear to have a bias against conservatives.
Republican Sen. Mike Lee, R-Utah, noted during Tuesday's hearing that nearly 92% of political donations from Facebook employees and nearly 99% of political donations from Twitter employees went to Democratic candidates.