Because of a shitty situation set up by countless past people and events completely out of your control you have to make a choice here. And in my mind, it's not even a difficult choice. Yes, either option will support Israel, that's a given, but there is no third option so it might as well not even be a factor in choosing a candidate.

If you want more parties and to remove first past the post then you need to elect the party who supports those stances. That is one of your two options. Real fucking simple.