If you were to log in, you'd be able to get more information on your fellow community member.
You're missing a couple of key points.
Israel is a democracy. America, especially lately, always attempts to support and preserve democracies, because we feel its in our interest to do so. We were less able to do this during the Cold War, and made some huge blunders in this regard (Iran, Vietnam). There's been a gradual shift in foreign policy since 1990 towards promoting democracy and human rights as a long term goal at the expense of short term goals.. I write about that here.
For a long time, US policy was for the Israelis and Palestinians to live together in harmony. We basically felt that the Israeli and Palestinian economies were too interdependent for them to survive separately. We've finally given up on that. Our current goal is for a separate state for the Palestinians, even if we end up with a "Tel Aviv" wall.