The Anti-Defamation League, one of the most prominent Jewish advocacy and anti-hate organizations in the US, removed over a thousand pages of extremism research from its site on Tuesday night following online backlash from rightwing influencers and Elon Musk.

The ADL’s now-deleted “glossary of extremism” contained over a thousand entries that gave background information on groups and ideologies connected to racist, antisemitic and otherwise hateful incidents. Its pages on neo-Nazi groups, militias and antisemitic conspiracies now redirect to the landing page for its extremism research.

Musk and prominent rightwing accounts on X had targeted the ADL in recent days over the glossary, which included an entry on slain far right activist Charlie Kirk’s organization, Turning Point USA. Musk also attacked the group for its page on Christian Identity, responding to posts on X that falsely conflated that extremist movement with Christians as a whole. In reality, the term refers to a movement which believes in a racial holy war against Jews and other minorities.

The ADL did not directly address the backlash in its statement on the decision and instead claimed the move would allow the organization to “explore new strategies and creative approaches to deliver our data and present our research more effectively”.

“With over 1,000 entries written over many years, the ADL Glossary of Extremism has served as a source of high-level information on a wide range of topics for years. At the same time, an increasing number of entries in the Glossary were outdated,” the ADL said in a statement. “We also saw a number of entries intentionally misrepresented and misused. Moreover, our experts have continued to develop more comprehensive resources and innovative ways to provide information about antisemitism, extremism and hate.”

The removal of the glossary comes as the ADL has faced intensifying criticism in recent years from staff and researchers over its narrowing mission to prioritize pro-Israel policies and its repeated defense of Musk. The group has lost donors and had one prominent executive resign following CEO Jonathan Greenblatt’s statements praising or defending Musk, which has not stopped the tech mogul from publicly attacking the organization.

The ADL did not respond to a question on what more comprehensive resources the group was referring to in its statement. The organization debuted its glossary in 2022, with the organization touting it as a first-of-its-kind database intended to help media, the public and law enforcement understand extremist groups and their beliefs.

“We believe it is the most comprehensive and intuitive resource on extremist speech currently available to the public,” said Oren Segal, senior vice-president of the ADL Center on Extremism, in a statement at the time. “We believe that an informed public is critical to the defense of democracy”.

The ADL’s page containing the 2022 press release now returns a message stating: “You are not authorized to access this page.”

Musk has long targeted the ADL and previously threatened to sue the organization for its work documenting the growth of antisemitic content on his social media platform. The ADL and Greenblatt came to his defense earlier this year, however, after other Jewish groups and lawmakers denounced what they described as him giving fascist-style salutes following Donald Trump’s inauguration. The ADL described it as an “awkward gesture in a moment of enthusiasm”.

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Musk repeatedly posted about the ADL’s inclusion of Kirk’s TPUSA in its glossary in recent days, calling the ADL a “hate group” and suggesting it encouraged murder. The entry for TPUSA did not state that the group was an extremist organization, but included a list of incidents of its leadership and activists associating with extremists or making “racist or bigoted comments”.

On Wednesday, Musk continued to post about the ADL and reiterated his claim that it was a “hate group”. He also joined in another rightwing pressure campaign, this time backing calls to boycott Netflix because one of its animated shows featured a transgender character.