The nation’s leading source of information on U.S. charities faces mounting criticism for using a controversial “hate group” designation in listings for some well-known and broadly supported conservative nonprofits.

GuideStar, which calls itself a “neutral” aggregator of tax data on charities, recently incorporated “hate group” labels produced by the left-wing Southern Poverty Law Center.

The decision by the tracker of nonprofits prompted 41 conservative leaders to protest the move in a letter provided exclusively to The Daily Signal. The letter, dated June 21, asks the website to drop the “hate group” labels put on 46 organizations. (Read the full letter below.)

GuideStar’s use of the “hate group” designation for certain organizations, many of them Christian, unfairly and inaccurately adopts the “aggressive political agenda” of Southern Poverty Law Center, the leaders write.

Among the organizations represented are the Family Research Council, the American Freedom Defense Initiative, the Immigration Reform Law Institute, the American College of Pediatricians, the National Task Force for Therapy Equality, the American Family Association, the London Center for Policy Research, and the Jewish Institute for Global Awareness.

In the letter to GuideStar President and CEO Jacob Harold, the conservative leaders write:

We, the undersigned organizations and individuals, write to express our strong disagreement with GuideStar’s newly implemented policy that labels 46 American organizations as ‘hate groups.’ Your designations are based on determinations made by the Southern Poverty Law Center (SPLC), a hard-left activist organization. As such, SPLC’s aggressive political agenda pervades the construction of its ‘hate group’ listings.

A biography of Harold on GuideStar’s website describes him as a “social change strategist.” He is seen in this tweet participating in the Jan. 21 Women’s March in Washington, D.C., which opposed new President Donald Trump:

Prior to joining GuideStar, Harold worked for the Hewlett Foundation’s philanthropy program, as a “climate change campaigner” for Rainforest Action Network and Greenpeace USA, and as an organizing director at Citizen Works.

Signers of the letter sound their concern that GuideStar, which calls itself a neutral public charity, is using the Southern Poverty Law Center’s much-contested language to flag “hate groups,” organizations that SPLC disagrees with.

“I think that what GuideStar is doing is another attack on conservative Christian organizations and individuals,” William G. “Jerry” Boykin, a retired Army general who is executive vice president of the Family Research Council, told The Daily Signal in an interview, adding:

We have seen the same thing from other places to include certain media outlets. GuideStar says that they are neutral, but they are anything but neutral. In fact, they are, I would say at this point, they are becoming an arm of the ultra-left.

Mat Staver, who also signed the letter and is the founder and chairman of Liberty Counsel, a legal group focused on religious liberty, told The Daily Signal in a phone interview he detects purposeful motivation behind GuideStar’s flagging.

“The intent there obviously is to harm, I think, these organizations,” Staver said.

Foundations, corporations, and other institutions look at listings by such organizations as GuideStar when they determine where to make tax-exempt contributions. They are unlikely to donate money to any organization labeled as a hate group, the conservative leaders argue.

A GuideStar spokesperson told The Daily Signal in an email Wednesday that the website will change some of the language:

GuideStar draws information from thousands of distinct sources, each of them imperfect. In aggregate, those sources help us offer a multidimensional view of nonprofits. However, we recognize that the SPLC data is especially controversial. We are changing the text description of this data and reconsidering where and how we present it on our website.

The changes will appear within a few days, the spokesperson said.

Family Research Council’s Boykin said GuideStar has two options.

“I think their choices are either take this label [down] that you have put on these different organizations, all of which are conservative Christian organizations, or acknowledge that you are a politically active arm of the liberal progressive movement in America,” he said.

Staver said his organization, one of those flagged by GuideStar as a hate group, asked Harold to promptly remove that label.

“So, 41 organizations are joining together, we are asking GuideStar’s CEO to respond to me within a very quick turnaround time to reverse its course and cease this false and defamatory labeling that it is using on its website,” Staver told The Daily Signal, referring to the letter.

Among the signers is Edwin J. Feulner, founder and president of The Heritage Foundation, the parent organization of The Daily Signal. Two other fixtures of the conservative think tank, Heritage board member Edwin Meese III and Heritage Action CEO Michael Needham, also signed the letter. Heritage is not labeled a hate group by either SPLC or GuideStar.

Organizations such as the Family Research Council are well aware of the implications of the messaging that GuideStar is perpetrating, Staver said.

Floyd Corkins, the man convicted of a 2012 attempt to massacre employees at the Family Research Council, was inspired by SPLC’s description of the Christian pro-family research organization as a hate group, he noted.

In an interview with the FBI, Corkins said a list on the Southern Poverty Law Center’s website motivated his attack. SPLC has acknowledged the connection.

The letter notes that James T. Hodgkinson, the man who police say tried to gun down Republican lawmakers last week, liked the Southern Poverty Law Center on Facebook.

House Majority Whip Steve Scalise, R-La., was gravely wounded in the gunman’s attack June 14 during practice for a congressional baseball game just outside Washington in Alexandria, Virginia.

“Does it not concern you that within the past five years, the SPLC has been linked to gunmen who carried out two terrorist shootings in the D.C. area?” the letter to Harold says, adding:

With these points in mind, we respectfully request that GuideStar return to its prior, nonpolitical approach to evaluating nonprofit organizations. Please send your reply within one week of receipt of this letter.

Read the full letter from 41 conservative leaders to GuideStar: