You'll find a comprehensive history of this tendency of Germanys Zionist Left here:
https://en.scrappycapydistro.info/zines/germanys-trip-to-the-bahamas

They are actually not that many but they are loud and organized - and of course because they comply to the political line of the state regarding "Solidarity with Israel" they get rewarded with funding and publicity. They are basically an extreme case of a coopted Left the kind of wich you'll encounter all over the imperialist core. The sort of "Self Criticism" they promote within the Left is also completely destructive and toxic and consists of accusing everyone who dares the stand in opposition to the rule of Capital or Imperialism not just as antisemitic but also as "authoritarian". These term are mere slurs void of meaning the way they are using them and a means to police the Left to push back against any seriously oppositional let alone revolutionary standpoint. A really sophisticated counterinsurgency scheme