This is because of antisemitism. Which leads me to believe that this is not an anti-Israel protest but a anti-Jew protest. One minute they deny the holocaust, next minute they call for a second holocaust. How can you call for a second if you haven't had a first?
Also people like these who hate Israel, 98% of the time it's because they hate the Jews. The other 2% just hate Zionism and the idea of Jews who fight back, so really they too hate the Jews as a whole.
And also to these types of people 'all Jews are Zionists and all Zionists are Jews'. I'm a Zionist, but I'm not a Jew. Those Neuter Karta guys are Jews but they're not Zionists. I just poked a big hole in their theory using logic and reasoning. And how did I do that so easily, because they're antisemites and an antisemite can always be beaten in a debate.