U.S. Rep. Ken Buck, who is also the chair of the Colorado Republican Party, has signed on to a letter from Republican members of the U.S. House Committee on the Judiciary asking Amazon to explain how its program allowing donations to charities penalizes conservative organizations.

Amazon’s CEO, Jeff Bezos, “acknowledged that Amazon relies in part on information from the Southern Poverty Law Center (SPLC) to exclude certain non-profits from participating in Amazon’s charity-support program, AmazonSmile,” the lawmakers wrote.

Under Amazon’s explanation of the initiative to donate 0.5% of purchases to charity, “Organizations that engage in, support, encourage, or promote intolerance, hate, terrorism, violence, money laundering, or other illegal activities are not eligible to participate. Amazon relies on the U.S. Office of Foreign Assets Control and the Southern Poverty Law Center to determine which organizations fall into these groups.”

The SPLC, founded in 1971, tracks extremist groups, publishes investigative reports and trains law enforcement, among other activities.

The Republicans on the committee alleged that SPLC “has baselessly labeled some conservative charitable organizations ‘hate groups’ alongside actual extremist organizations such as neo-Nazis and the Ku Klux Klan.” Specifically, they mentioned the Alliance Defending Freedom and the Family Research Council as prohibited from receiving AmazonSmile donations.

The SPLC says its definition of “hate group” encompasses organizations that “attack or malign an entire class of people, typically for their immutable characteristics.” In the case of the ADF, SPLC labeled it an “anti-LGBTQ hate group.” The organization is currently representing a Colorado woman seeking to deny website design services to same-sex couples. One employee of the ADF countered that SPLC’s labels were akin to a “bully who calls names.”

SPLC also designates the Family Research Council as promoting anti-LGBTQ hatred; a 72-page report posted to that group’s website on Aug. 20 stated that “homosexuality is a consequence of humanity suppressing God’s truth and refusing to honor Him.”

The Republican representatives said that exclusion from AmazonSmile would result in less exposure and fewer donations to those groups. In October 2018, Amazon announced it had donated $100 million through the program.