> One older man out of nowhere loudly proclaimed I was Anti-semetic

There's a bit of fringe-political subculture worth knowing here. Most self-proclaimed antifascist groups in Europe are made up of leftists who side with the Palestinians, and in Germany that scene has a long history of friction with old-school "anti-imperialists", often fairly authoritarian communists. The "antideutsche" current grew out of a rejection of exactly that, dating back to reunification in 1990, when part of the radical left decided the real danger was Germany itself. It started as a mostly intellectual critique, but in practice it came to mean waving the Israeli flag at every opportunity and giving grief to anyone in a keffiyeh.