The union I lead, the United Steelworkers (USW), believes in unity, that “all working men and women, regardless of creed, color or nationality” are eligible for membership.

That was the guiding principle of the Steel Workers Organizing Committee (SWOC) when it formed in 1937.

I return to that statement in times like these, times when terrorists shoot up mosques in Christchurch, New Zealand, killing 50 worshipers; a synagogue in the USW’s hometown of Pittsburgh, killing 11; an African Methodist Episcopal Church in Charleston, South Carolina, killing nine; a Sikh temple near Milwaukee, killing six; a nightclub in Orlando, killing 49 mostly young gay people.

The USW membership eligibility statement is an assertion of inclusion. All working men and women qualify. They can all join. They can all attend local union meetings at which members call each other “brother” and “sister.” This practice creates artificial, but crucial, bonds between them. This solidarity gives the group strength when facing off against massive multinational corporations and demanding decent pay and dignified working conditions.

To erode that solidarity, some billionaire hedge fund owners and multinational CEOs work to divide workers. These wealthy .01 percenters separate people by cultivating hate. Some are the same billionaire sugar daddies of alt-right hate sites like Breitbart and more conventional hate media outlets like Fox News. Investigative journalist Jane Mayer wrote a book about their efforts titled Dark Money: The Hidden History of the Billionaires Behind the Rise of the Radical Right.

This hate-mongering sets workaday people against each other. That weakens them politically. And it contributes to false-fear–provoked violence.

Look, the labor movement is far from perfect. A couple of decades ago, African-American USW members had to sue steel corporations and the union to secure equal opportunity. Clearly, we haven’t always lived up to our principles. But the goal of brotherhood and sisterhood among all workers is a noble one that must be strived for. We all sweat together to support ourselves and our families. We all come to each other’s aid when a fellow worker’s home burns down or child falls ill. We stand shoulder to shoulder to demand a just portion of the profits created by our labor.

Exclusion is self-defeating, whether workers belong to a labor union or not. Because every man and woman is needed on deck, we can’t let billionaire hate purveyors like the Mercers and Murdochs split us, in our workplaces or in our communities.

Robert Mercer, 72, who made his billions as a hedge fund manager, is a major funder— more than $10 million —of Breitbart, the website once run by former White House aide Stephen Bannon. This is what the Southern Poverty Law Center, an organization devoted to monitoring and exposing domestic hate groups and extremists, wrote about the site:

“In April of 2016, the SPLC documented Breitbart’s embrace of extremist ideas and racist tropes such as black-on-white crime and anti-Muslim conspiracy theories. Further analyses showed how under executive chair Stephen Bannon, Breitbart’s comment section became a safe space for anti-Semitic language.”

Bannon specifically told Mother Jones magazine that Breitbart was the platform for the alt-right, which has lifted anti-Semitic and white supremacist voices.

At the same time, the Mercers, Robert and his daughter Rebekah, were giving millions to right-wing anti-union groups through the Mercer Family Foundation . These include the virulent anti-union Heartland Institute ( $6.68 million ), Heritage Foundation ( $2 million ), CATO Institute ( $1.2 million ) and Manhattan Institute for Policy Research ( $2.18 million ).

It includes the Center for Union Facts ( $900,000 ), a secretive group for corporations and wealthy individuals who oppose unions and who are willing to fund its lies about labor organizations, and the Freedom Partners Action Fund ( $2.5 million ), which, in turn, has given millions to anti-union groups like the National Right to Work Committee . And the Mercer Foundation gave $100,000 to the State Policy Network, the umbrella group for 100 state-level organizations devoted to destroying labor organizations .

The media mogul Rupert Murdoch, 88, is a slightly older version of Robert Mercer. He made his feelings about labor unions clear 30 years ago when he moved his London newspaper operations overnight to a barbed-wire–enclosed bunker in the neighborhood of Wapping and told unions he’d fire all workers who did not immediately transfer to the new building and use its new technology. When the print unions resisted, Murdoch fired 5,500 printers .

He also served on the board of directors of the anti-union CATO Institute. Murdoch, who is worth about $20 billion, is listed as chairman and president of a Murdoch Foundation , but it has no assets and has made no grants in more than a decade.

On Fox News, the television network controlled by Murdoch, numerous commentators, including the currently suspended Tucker Carlson and Jeanine Pirro, are openly hostile to labor unions and are viciously anti-immigrant and anti-Muslim. The Council on American-Islamic Relations has called for advertisers to boycott Fox News unless it fires Carlson and Pirro.

A former senior vice president at Murdoch’s News Corp, Joseph Azam, told National Public Radio this week he left his job in 2017 over the network’s coverage of Muslims, immigrants and race. The NPR story says , “the rhetoric coming from some of his corporate colleagues sickened him: Muslims derided as threats or less than human; immigrants depicted as invaders, dirty or criminal; African-Americans presented as menacing; Jewish figures characterized as playing roles in insidious conspiracies.”

Last weekend, a Muslim news producer, Rashna Farrukh, announced that she quit Fox’s corporate cousin, Sky News Australia, over its coverage of Muslims on the days after the massacre at the two Christchurch mosques. She wrote this in a post for ABC News :

“I compromised my values and beliefs to stand idly by as I watched commentators and pundits instill more and more fear into their viewers. I stood on the other side of the studio doors while they slammed every minority group in the country—mine included—increasing polarization and paranoia among their viewers.”

Billionaires such as Murdoch and Mercer wield immense power. Organizations they stealth-fund are dedicated to dividing and conquering workers. They’re dangerous because they breed, broadcast and promote hate.

The only way to deal with them is with solidarity. Workers must have each other’s backs. They must see each other as brothers and sisters. Their guiding principle must be that all working men and women, regardless of creed, color, nationality or sexual orientation are welcome.