Facebook, Twitter and Google have become political footballs for the left and right. This week, Congress get its kicks in

Facebook, Google, and Twitter find themselves on the defensive from both ends of the political spectrum. And they have no one to blame but themselves, critics say.

To grow their businesses, tech platforms replaced print media and network news as the chief distributors of information. And they’ve taken pains to appear neutral — not the least because they don’t want the complicated job traditionally assigned to journalists of determining what’s fact and fiction.

But in the Trump era, where notions of truth have rarely been viewed through a more partisan lens, being neutral means having to deliver conspiracy theories such as “Pizzagate,” which imagined a child sex ring being run out of a pizza restaurant in Washington, to users who believe in them.

“They have warmly embraced the margins … but are allergic to the responsibilities,” said Scott Galloway, a professor of marketing at NYU Stern School of Business and author of “The Four: The Hidden DNA of Amazon, Apple, Facebook and Google.”

The tech giants’ predicament will be on full display Wednesday as top executives at Facebook, Twitter and Google are scheduled to testify at contentious hearings in Washington.

At the first hearing Wednesday, Democratic members of the Senate Select Committee on Intelligence will likely grill Facebook Chief Operating Officer Sheryl Sandberg, Twitter chief Jack Dorsey and Google co-founder Larry Page — if he agrees to show up — about safeguarding their networks from foreign influence after allowing Russian actors to run amok during the 2016 election.

Later in the day, Republicans on the House Energy and Commerce Committee will confront Dorsey about perceived liberal biases stifling conservative viewpoints on Twitter — a grievance that was amplified last week by President Trump’s tweets and remarks attacking the platforms.

“I think what Google and what others are doing, if you look at what’s going on at Twitter, if you look at what’s going on in Facebook ... they better be careful because you can’t do that to people,” Trump said at the White House on Aug. 28. The same day, he accused Google of promoting negative search results about him. “So I think that Google, and Twitter and Facebook, they are really treading on very, very troubled territory and they have to be careful. It’s not fair to large portions of the population.”

Conservatives have adopted a hashtag on social media as a rallying cry: #StopTheBias. It was used in a tweet by the president Wednesday that falsely accused Google of promoting President Obama’s State of the Union addresses, but not Trump’s.

On Thursday, Trump told Bloomberg that the firms may be in a “very antitrust situation.”

Silicon Valley can’t please the left because of its failures during the 2016 presidential campaign to block misinformation and hate speech. And now it can’t please the right because its crackdown on misinformation and hate speech has ensnared Trump supporters like Alex Jones.

“It’s a problem they themselves designed,” said Gabriel Kahn, a professor at the USC Annenberg School for Communication and Journalism. “These platforms are designed to repeat back to us our most closely held beliefs and insulate us in an ideological bubble of comfort.”

The companies are even hearing it from their own employees. Dozens of Facebook workers have joined an online group calling for more political diversity in an industry that’s overwhelmingly liberal, the New York Times reported Aug. 28.

“We are a political monoculture that’s intolerant of different views,” Facebook engineer Brian Amerige wrote in an internal Facebook message board. “We claim to welcome all perspectives, but are quick to attack — often in mobs — anyone who presents a view that appears to be in opposition to left-leaning ideology.”

The message echoes the more barbed sentiments of former Google engineer James Damore, a conservative who described his then-workplace as an “ideological echo chamber” in a controversial memo last year that ultimately cost him his job. He also suggested the company’s gender gap could be explained by biology rather than discrimination. Companies have no obligation to uphold free speech; 1st Amendment rights only apply to government entities.

Venture capitalist and Facebook board member Peter Thiel also decried Silicon Valley’s liberal leanings and announced in February he was leaving for a more inclusive political environment. Curiously, he chose Los Angeles.

How exactly Silicon Valley is expected to hire more conservatives in a field that traditionally attracts liberal workers is unclear, experts say. Recruiters aren’t allowed to ask whom prospective employees voted for.

“The suggestion that Silicon Valley is intentionally anti-conservative is vastly overblown,” said Dipayan Ghosh, a fellow at Harvard Kennedy School’s Shorenstein Center and a former privacy and public policy advisor at Facebook.

“In recent weeks, a relatively few vocal conservatives within leading tech companies have voiced their concerns. While they are correct that there are many more liberals than conservatives who work in the industry, it’s not the case that these companies are proactively discriminating against conservatives. And it’s not a company’s responsibility to assure that it hires equal numbers from both sides of the political spectrum.”

It’s against this backdrop that Sandberg, Dorsey and Page, who has yet to accept the invitation to appear, must testify. All three companies have taken various steps to prevent foreign influence and promote transparency in their advertising. They also strongly deny harboring liberal biases.

Google said its search engine is not used to promote a political agenda.

Twitter says it employs people who have previously worked for Democratic and Republican lawmakers. It insists it has no interest in drowning out perspectives on a platform designed to exchange ideas.

Facebook said suppressing what conservatives want to watch and read would undermine its mission and business objectives.

“We do not suppress content on the basis of political viewpoint or prevent people from seeing what matters to them,” said Facebook, which announced in May that former Republican senator Jon Kyl would lead an inquiry into alleged bias against conservatives.

Yochai Benkler, a professor at Harvard’s Berkman Klein Center for Internet and Society, said there’s no evidence that the platforms are censoring right-wing content. Rather, he said, the complaints of bias are designed to make the companies hypersensitive to conservative interests — which, in this case, concerns attacking the credibility of the mainstream media.

“I think what the president and right-wing media are doing is exactly what they’ve been doing with mainstream journalists: working the referee,” said Benkler, who co-wrote the new book “Network Propaganda: Manipulation, Disinformation, and Radicalization in American Politics,” which examines millions of online articles, tweets and Facebook posts.

A search algorithm designed to favor credible news sources that employ basic tenets of fact-based journalism could be viewed as biased by some conservatives because right-wing media have shifted so far from the center, Benkler said.

“Given how consistently all the top sites in the right-wing media ecosystem amplify and lend credence to pure partisan disinformation,” he said, “all you need in order to be ‘left’ is to adhere to standard norms of journalism or science.”

david.pierson@latimes.com | Follow me @dhpierson