For a member of the military to refer to someone as “Sir” or “Ma’am” is (usually) a sign of respect. For example, I always address my superiors as “Sir” or “Ma’am”–and I expect the enlisted folks I work with to show that respect to me by calling me “Sir”.
So in watching this clip I can only think that Senator Barbara Boxer is a bit pretentious to refuse this honorific–either that, or she is very out of touch with reality. Watch and let me know if you think otherwise.