We stand for those we respect, either voluntarily or compulsorily, according to social norms.
We stand for the judge AND the jury in a courtroom. Soldiers stand at attention for their commanders. Does everyone stand for the President? (I'm thinking of the press corps - do journalists stand at a press conference when the President enters?) Here in the Deep South, some of us stand for women whenever they stand, and sit after they sit.
I suspect standing for an authoritative figure goes back to emperors and kings, who were usually military leaders. Standing for self-proclaimed religious leaders has its tradition in the Catholic Church - not 1st century, not Paul (as much as he would have loved the attention).
If one has to whine about others standing for him, one doesn't deserve the gesture of respect. Whining about such a thing tips one's hand to one's illegitimacy.