Where does criticism of the Israeli government end and where does anti-Semitism begin?
Criticism of Israeli government policy is not anti-Semitic per se and we Germans can also criticize it - just as Israelis themselves do. The settlement policy in the West Bank, for example, violates international law. It is absolutely possible to criticize this without being accused of anti-Semitism. Criticism becomes anti-Semitic when Israel's right to exist is called into question. Or when Israeli actions are compared to the atrocities committed by the Nazis.
Do you have an example?
Criticism of Israeli government action is absolutely legitimate. Anyone who criticizes the settlement policy that violates international law or the course of the protective wall between the West Bank and Israel is not anti-Semitic. But anyone who denies the state of Israel the right to exist and lets loose a slogan like "From the river to the sea, Palestine will be free" is making an anti-Semitic statement. When Israeli government actions are equated with Nazi crimes and, for example, the Gaza Strip is described as a large concentration camp, then this is also anti-Semitic because it relativizes Nazi crimes and reverses perpetrators and victims.