And isn't that the point - saluting is a courtesy, and let us call them compliments rather than marks of respect. Whatever one may personally think of the individual, it is discourteous to withold a salute as it is to fail to return one. One thing that sets the Services apart is that we retain (in the face of cuts and mismanagement) both professionalism and politeness.
I can show respect for uncased colours, funeral corteges and
the national anthems of foreign states, but if I really want to show my contempt for poloticians and undeserving senior officers, then my salute must be especially crisp.
By all means salute the Prime Minister, but address him as Mr Blair, not, as he would wish, Tony, or Sir.