As I said to a fellow denizen of the net, Arun Gandhi got into this pickle because he is unable to calibrate a principle "non-violence" against place/public policy. For example, he himself agreed that nonviolence can only work against a liberal society such as the UK. In other words, if he had practiced this non-violence principle against say Beria or Stalin, well, I wouldn't bet on that principle working.
In this case of Jews and Hitler, Mahatma Gandhi suggested that they all go happily to their deaths as part of non-violence and belief in god. Well, they did, millions of them. (even if this "happily" is debatable!) And? It still took a war to get rid of Hitler. So that kind of public policy advice is rather silly. (Mind you, his suggestions to the Arabs was even more silly!)
And now this is even sillier. Also it shows the lack of understanding of the religion by concentrating so much on the holocaust. While I am not an expert on Zionism, I do think that while the holocaust did play its part, one forgets the civilisational and religious drive behind Zionism going back to the slavery in Egypt and and exile in Babylon millennia ago. So the Zionist philosophy is based upon much deeper, longer and broader factors than just the Holocaust. It borrows and rests on a very hard set of religious facts and emotions. So resolving the Palestinian question cannot be done by just looking at the Holocaust.
Before his apology, yes, his statement could be construed as anti-Semitism, but I am giving him the benefit of doubt (to use a cricketing metaphor!) and accepting his apology and explanation.
As for his statement about thousands of people marching across the Jordan River in a non-violent protest, actually that is a good tactic because Israel will not be able to resist it, but Palestinians, for a variety of reasons, will not be able to do this. See here for a more detailed debate about the applicability of this principle. But, unfortunately, Arun Gandhi tried to parlay his family name and all he managed to end up doing was to commit the same mistake that the Mahatma committed with respect to this issue.