Corporate America, take note: Relying on the Southern Poverty Law Center’s “hate” and “extremist” labels could make a liar out of you—and cost you millions of dollars.

It wasn’t always like this. Decades ago, SPLC built its reputation as a trusted civil rights watchdog by valiantly fighting the Ku Klux Klan. But it has wandered far from its roots.

Today, SPLC raises hundreds of millions of dollars and pads its off-shore accounts by slandering people and organizations who disagree with its far-left views.

We all received a dramatic reminder of this a few days ago, when SPLC settled British activist Maajid Nawaz’s threatened defamation lawsuit over its branding him an anti-Muslim extremist. SPLC issued a public apology and paid Nawaz a whopping $3.4 million.

But we shouldn’t need reminders to distrust SPLC. Commentators across the political spectrum have repeatedly warned that the organization has devolved into nothing more than a progressive hit group. Here are a just a few assessments:

—Mark Pulliam wrote in City Journal that “the SPLC not only overlooks most of the real hate groups in operation today … but also labels moderates with whom it disagrees ‘extremists’ if they deviate from its rigid political agenda, which embraces open borders, LGBT rights, and other left-wing totems.”

—Cornell law professor William Jacobson said: “Time and again, I see the SPLC using the reputation it gained decades ago fighting the Klan as a tool to bludgeon mainstream politically conservative opponents.”

—Muslim reformer Ayaan Hirsi Ali, who SPLC infamously tagged as an anti-Muslim extremist, describes the group this way: “[T]he SPLC is an organization that has lost its way, smearing people who are fighting for liberty.”

—Of SPLC’s notorious “Hate Map,” which lists every group it deems a “hate group,” Kimberley Strassel wrote in The Wall Street Journal: “Since SPLC is a far-left activist group, the map comes down to this: If the SPLC doesn’t agree with your views, it tags you as a hater.”

—Writing for The Week, Shikha Dalmia lamented that “the SPLC is not up to the task” of monitoring actual hate groups because “[i]t is too busy enforcing liberal orthodoxy against its intellectual opponents.”

—Even left-of-center Politico—in an article headlined “Has a Civil Rights Stalwart Lost Its Way?”—noted that SPLC has long been criticized for “becoming more of a partisan progressive hit operation than a civil rights watchdog.”

Despite article after article showing that SPLC has lost its credibility, some media outlets, major corporations, and other third parties continue to uncritically repeat the group’s propaganda and rely on it to enforce their own policies.

This has real-world consequences for those SPLC maligns.

For example, Amazon excluded my legal organization, Alliance Defending Freedom, from the Amazon Smile program solely because SPLC had labeled ADF a “hate group.” It did so because we protect from government discrimination people who believe that marriage is a union between one man and one woman—a belief held by millions and taught by diverse faith traditions ranging from Islam to Christianity.

SPLC’s designation of Alliance Defending Freedom as a “hate group” is, quite frankly, preposterous. With nine wins in the past seven years at the U.S. Supreme Court and hundreds of victories protecting student speech at America’s public universities, ADF is one of the nation’s most respected legal organizations working to protect our constitutionally protected free speech and religious freedom rights.

In fact, just this month, ADF notched a key victory at the U.S. Supreme Court for those who want to live peacefully according to their beliefs about marriage. In that case—Masterpiece Cakeshop v. Colorado Civil Rights Commission—the Supreme Court ruled that Colorado violated cake artist Jack Phillips’ First Amendment rights when it ordered him to create a wedding cake celebrating a same-sex marriage.

SPLC’s propaganda also cripples the prospect for civil dialogue. Tolerance and respect for those with whom we disagree are essential in a diverse society such as ours. They enable us to coexist peacefully with each another.

The group’s tactics run counter to these crucial commitments. They shut down debate and breed contempt for—and sometimes inspire violence against—those who hold different views.

Twitter, Facebook, YouTube, and other tech giants intensify these problems by relying on SPLC to police so-called “hate speech” on their platforms. The outlook for free and open dialogue in the digital marketplace remains dim so long as these corporations partner with far-left advocacy groups such as SPLC.

It’s long past time for media corporations, Silicon Valley, and others to stop relying on the Southern Poverty Law Center. They shouldn’t wait until they are swept up into litigation over SPLC’s next multimillion-dollar lie to get the message.

But that’s exactly what it might take, given how entrenched SPLC seems to be in corporate America.