Holding all Jews accountable for the actions of Israel is almost as conscionable as holding you responsible for Hitler's actions, or holding me responsible for Bin Laden's. I.e. it's utter bullshit.
While it could be a subset of Israel, various forms of Zionism also come to my mind. It's interesting how the Israeli PR is so effective in some cases (like in US government) and so ineffective in others. Of course I have to remind myself that P(bad person | jewish) isn't significantly different from P(bad person | not jewish), we're all human.