Look at a map. See where the settlements are, and see where the Palestinians live. Then locate the "wall". Try to draw some alternative map for the wall which will keep in the Jewish settlements while keeping out the Arab communities. If it can be done at all, the wall would need to be as long as the Great Wall of China, so much weaving in and out would be necessary. Israel needs defensible borders, especially with its Palestinian neighbors. The already crazy path of the wall would be far crazier if these settlements were inside. It is simply unfeasible. Compromises must be made in the name of security.