Is diplomacy inherently political? Are diplomats politicians?

Yes. While we think that diplomacy should not be political, it is. Diplomats serve at the discretion of the President. If they act in a way that is different to that of the President's plan then they can and have been removed. Diplomats must be politicians. They are abroad in other nations working with other politicians to work out what would be best for our nation. They act very similar to lobbyists in our own government.