The ADL is an Israeli/Zionist advocacy group at its core. It's main priority as an organization is to protect Israel and its mission for a Jewish Ethno-State. This is especially true under Johnathan Greenblatt's leadership who has said "antizionism is antisemitism"
It's easy to think that the "Anti Defamation League" has no underlying agenda given its history as a "civil rights organization" but it has constantly used that as a screen for extremely right wing positions on Israel.
Some of their greatest hits include:
Equating Students for Justice in Palestine, JVP, and CAIR to "white supremacists" simply because they strongly oppose an ethnic cleansing of Palestinians.
A leaked ADL memo revealing how ADL plans to "soften" the news to Americans that Israel plans to annex the West Bank. (Source). In this leak Greenblatt recognizes that the annexation is a violation of basic human rights. To me this is a clear indication that they are less concerned with civil rights and more concerned with shaping the public image of Israel, especially in the US. Really urge you all to read this leak!
Supported South African Apartheid (surprise surprise) and participated in propaganda against Nelson Mandela and the ANC. They even employed a spy named Roy Bullock to infiltrate the anti-apartheid campaign in the US. They later settled a law suit for this. (Source)
That's not even close to the only time they've utilized spies. THIS recent leak of Greenblatt talks about ADL having spies in Jewish Voice for Peace and other organizations. It also talks about how they are having a hard time with the global youth no longer buying into their propaganda. Another source you should give your full attention to. PLEASE listen to that whole thing. It's truly terrifying. You're gonna hear them talk a lot about why Tiktok is a danger to their mission.
HERE is an article about how the ADL has a long history of smearing black activists, working with Police/ICE, and its attempts to demonize the BDS movement.
I could go on and on about how terrible and deceitful the ADL is. The sources above are a good start to understanding why we shouldn't trust the ADL but please look into all the other things they've done like working with the FBI to spy on Arab Americans, infiltrating student organizations they find to be a threat to "Israel's image", surveillance, the people who fund/donate to them etc.
The best way to fight orgs like this is to share/spread this info as much as you can. It's clearly working because they're losing global support especially with the youth.