(NewsNation) — A release of internal Twitter documents dubbed “Twitter Files” has revealed accounts were placed on various “blacklists” that sought to limit the reach of accounts, including that of a doctor who expressed concern over COVID-19 lockdowns.

Stanford professor Dr. Jay Bhattacharya was “blacklisted” for raising questions about how school lockdowns might affect the nation’s children. He joined NewsNation’s “On Balance” on Friday to discuss the revelation, saying he was surprised that “Twitter would take on itself the suppression of scientific discussion.”

“I have not been abusive, I’ve not said a single swear word on any of the platforms,” Bhattacharya said. “Frankly, I’m not even sure it was political. I was basically arguing for something like the Swedish approach, which is a left-wing, more socialist kind of idea toward school openings and lockdowns.”

For example, in a pinned Tweet on Bhattacharya’s profile, he says: “Mortality from #COVID19 differs more than a thousand-fold between the old and young. Focused protection is the compassionate approach that balances COVID risks and collateral damage to public health.”

Twitter’s moderation policies became a great source of debate during the pandemic when the social media platform began flagging and labeling tweets as containing misinformation.

In one of the internal files released by former New York Times columnist Bari Weiss, Bhattacharya’s account is marked as having a “recent abuse strike” and as being on a “trends blacklist,” which would have prevented his tweets from trending.

He said he was shocked to find confirmation of what had been rumored for some time. Former CEO Jack Dorsey in a congressional testimony denied the company shadowbanned accounts.

“If Twitter thought of itself as a free speech vehicle, why would it reduce the visibility of a prominent point of view on the lockdowns?” Bhattacharya said. “It makes no sense.”

Other accounts that were placed on blacklists, according to the internal documents, include right-wing talk show host Dan Bongino and conservative activist Charlie Kirk. Conservatives and Republicans in Congress have repeatedly argued that Twitter and Big Tech companies are censoring their opinions and disregarding principles of free speech.

Social media companies argue they only suspend accounts when people violate their policies, such as by using hate language or inciting violence.

Bhattacharya says he’s done nothing of the sorts and is no partisan.

“I’m a public health scientist, I work for the people. Sometimes my thoughts are taken up by the left, sometimes it’s by the right,” Bhattacharya said. “During the pandemic in the United States it’s been associated with a right-wing position, and if I were writing in Sweden, it would have been associated with a left-wing position. It’s just my thoughts about the best way to manage the pandemic to minimize the harms to children, the poor and the working class.”

Congressional Republicans have vowed to investigate the censorship claims when they take control of the House in January. Of particular interest is whether the Biden administration was working in coordination with Twitter or other social media companies to de-amplify certain accounts and opinions.

“It’s I think not an accident that I showed up in the blacklist,” Bhattacharya said. “I was arguing for policy that was very different than the policy the Biden administration followed regarding COVID, and to see that Twitter did this, it’s really hard to believe that they did it entirely on their own.”