The overall balance is still in favor if Israel, no matter how you cut it. One can argue that Europeans are only being consistent. Besides, if you kill their guilt, they may turn away from both Arabs and Israelis and stop paying attention to multicultaralism and charges of racism and anti-semitism, which are a tool to affect their policies.
The argument that liberals are better than neocons because neocons are the same liberals but less honest and consistent ones and therefore more dangerous is certainly attractive. Neocons are those Israel-firsters who decided that they can lobby for Israeli interests more effectively once principles of liberalism are discarded. Of course, with their being conservatives in name only, their ideology is an inconsistent mix of ideas that favor their agenda only. This is similar to the sentiment that European guilt was once good for the Jews, and now it's not.
Under what principles of "conservatism" does one's own country support one particular other country in its tribal and territorial disputes with its own inhabitants and its neighbors?
There are none.