On those occasions he was polite and and engaged in conversation with both flight deck and cabin crew but it is very rare!
Of course he was. You don't expect him to be rude, do you? Most of the people are polite in first encounters with other people. It means nothing in relation to the fact that he is the first among managers in EK.
That Sir title is only valid and only means something in UK. For the rest of us it can really say "Mute TC", what do we care for UK titles...