He became known for his public statements in German news media as an expert on German-Israel relations and for his work in educational projects to combat racism and antisemitism.

Under his leadership, the centre expanded its activities with a multimedia learning laboratory for young people, two counselling units for victims of right-wing violence,[1] as well as exhibitions, for example on The Holocaust in comics.

"[16] In 2019, Mendel described the decision of the city of Frankfurt, not to provide urban venues to the BDS movement, as a "strong signal against hatred of Jews and Israel-related antisemitism.

"[17] Criticizing antisemitism in German cultural life, Mendel denounced a mural depicting negative caricatures of Jewish characters and symbols by an artists' collective from Indonesia at the 2022 art fair documenta fifteen.

[22][23] In a review by the NDR public broadcast his views in the "excited permanent discussion" on the Middle East conflict were judged as "pleasantly differentiated.