I think it’s this

Volksverhetzung, in English “incitement to hatred” (used also in the official English translation of the German Criminal Code),[1][2] “incitement of popular hatred”, “incitement of the masses”, or “instigation of the people”, is a concept in German criminal law that refers to incitement to hatred against segments of the population and refers to calls for violent or arbitrary measures against them, including assaults against the human dignity of others by insulting, maliciously maligning, or defaming segments of the population.

I think being anti-Israeli actions is enough but being anti-Jewish would be. And “death to Jews” definitely counts

During an April 2023 pro-Palestine protest, observers recorded numerous antisemitic chants, including “Death to the Jews”.[25][26] The Berlin Police have confirmed they are investigating charges of Volksverhetzung;[25] two pro-Palestine demonstrations planned for the following weekend were cancelled

From the article you’re commenting on:

The suspects were said to have celebrated the attacks by Palestinian militant group Hamas on Israel on Oct. 7, and were accused of spreading hate speech against Jewish people on social media, using symbols of banned terrorist organizations, dpa reported.

and

One suspect allegedly sent a sticker in a WhatsApp school class chat with the words “Gas the Jews.” Another person, a German-Turkish dual citizen, allegedly posted on his account that “the Jewish sons” deserved nothing more than to be “exterminated,” dpa reported.

So probably more the category “celebrating antisemitic terrorism” and “calling for the extermination of all Jews.”