Wikipedia left biased edits on Israel, Hamas, and Zionism pages intact despite bans, ADL finds

Uncorrected past biased edits remain embedded across Wikipedia's most-read pages concerning Israel, Zionism, Hamas, and Jewish history, according to a follow-up report published by the Anti-Defamation League's (ADL) Center for Technology and Society on Thursday.

The report, titled Damage Done: Wikipedia Leaves Biased Edits Unchecked Despite Editor Bans, follows an initial investigation released in March 2025 titled Editing for Hate, which documented a coordinated campaign by approximately 30 bad-faith editors to manipulate entries related to Israel, Jewish history, and the Israeli-Palestinian conflict.

Following the release of that initial investigation, the findings became the subject of extensive external pressure, including a US. House Committee on Oversight investigation, a bipartisan congressional letter signed by 23 members, and federal inquiries from the Department of Justice and the Senate Commerce Committee, alongside widespread media reporting and scrutiny from Wikipedia's own neutral-point-of-view editors.

To understand how editor behavior and article content have changed since their previous investigation, researchers analyzed platform activity using five separate data collections gathered between July and August 2026. These methods included tracking whether edits made by banned users remain live on major pages, comparing editing volumes before and after the 2025 report, and reviewing thousands of revisions and discussion logs across conflict-related entries.

As part of this methodological analysis, the ADL examined public platform communication records and collaboration patterns on Wikipedia. Following the intense external scrutiny, visible coordination metrics among the bad-faith editors dropped sharply. Public user-talk page messaging between group members fell 95.41 percent from 501 down to 23, and same-page tandem editing dropped 87.91 percent from 6,218 down to 752. Total combined edits across the group decreased by 26.65 percent from 182,440 down to 133,817.

According to the report, although Wikipedia's Arbitration Committee topic-banned six editors and site-banned three, it did not systematically review or correct any of their work. On six flagship articles, including Hamas, Gaza war, Zionism, and October 7 attacks, 91 percent of past edits made by Iskandar323, an editor identified in the original 2025 report who was subsequently site-banned for violating platform rules in the topic area, remain intact in the live text.

A July 2026 review identified 19 active accounts shaping conflict-related pages: eight unsanctioned members from the original cohort and 11 newly identified editors. These accounts use subtler techniques, such as gatekeeping through frequent reverts that undo neutral updates, hedging factual claims with qualifiers to turn documented facts into contested opinions, and gradually rewriting or restructuring page sections so no single edit draws administrator attention.

To see how these active accounts shape the current content, researchers tracked who made the most recent change across these Wikipedia pages. Out of 229 articles touched by these accounts, newly identified editors hold the final and current version on roughly six in ten pages 144 of 229, as well as two-thirds of the pages edited by both the old and new cohorts 95 of 142. Furthermore, editors flagged in the report heavily rewrote and managed the content on October 7 sexual violence, accounting for 832 out of 9,576 total revisions, roughly one out of every 11 edits, across those specific articles and their accompanying discussion boards where disputed wording is actively negotiated.

The report detailed several notable examples of enduring distortion. Three days after the October 7 attacks, on October 10, 2023, an editor relocated material concerning Hamas's antisemitism, human shields, child combatants, and human rights abuses into a far less-read page titled Criticism of Hamas. At the time, the main Hamas page drew close to one million views per day, so readers arriving at the primary entry no longer encountered that critical material unless they navigated to the secondary article. Consequently, the main page's lead section does not identify Hamas as a designated terrorist organization until its very end.

In November 2023, approximately 17,000 characters were removed from the Gaza war article, deleting forensic documentation of victims bound with wire, burned bodies, and attempted decapitations, followed by another cut of roughly 7,400 characters. What remains is a single line stating that terrorists "reportedly engaged" in such violence.

A newly identified account made 543 edits to the Zionism article, adding roughly 193,000 characters and removing approximately 188,000. The resulting lead defines Zionism as achieved "through colonization" and states as fact that Zionists sought a state with "as few Palestinian Arabs as possible," language Wikipedia's own editors have internally flagged as disputed and which was locked in place after a 12-month administrative moratorium.

Following the February 2025 return of the bodies of Shiri Bibas and her young sons Ariel and Kfir, an unsanctioned original-cohort editor made 64 edits to their article and discussion page, holding the manner of their deaths open despite Israeli forensic conclusions that they were murdered in captivity.

Daniel Kelley, senior director of the ADL Center for Technology and Society, said, "Even in cases where the Wikipedia community took some modicum of action against editors who went against their policies, the activities of that banned editor remain in this case activity over numerous years driving an ideological narrative in flagrant violation of the neutral point of view policy of the platform."

“This speaks to a systematic issue with how Wikimedia allows their platform to operate, and it is something they have the responsibility to address,” Kelley added.

ADL CEO Jonathan Greenblatt said, "Banning individual editors was never going to be enough. The pages that millions of people read, and that AI tools learn from, still bear the marks of a systematic disinformation campaign that Wikipedia itself has sanctioned but never cleaned up."

Greenblatt further stated, "The most visited online encyclopedia that claims neutrality has to be willing to repair its own record. The Wikimedia Foundation should audit this work, and the companies that build search and AI products should stop presenting contested framing as settled fact."

Because Wikipedia feeds directly into AI training pipelines, Large Language Model outputs, and search engine results, the ADL has renewed calls for structural reforms. These recommendations include private identity verification for editors in contentious topic areas, ending anonymous IP-address editing, establishing a dedicated task force on antisemitic bias, and conducting structured content audits of heavily edited articles.