There's no objective standard for morality or decency. They are inherently relative and everyone has their own standard. Some may think wearing a revealing bikini at the beach is indecent while other go to full nude beaches and see nothing wrong with that.
OTOH, many cases they overlap - most people think murder is immoral.
As for morality in a leader, his or her sense of morality should guide their actions, but face facts - being a leader sometimes means to commit cold blooded murder if the target is OBL or that Sinwar guy. If you think that's too immoral then maybe you shouldn't be a leader. In fact leaders rank high on the psychopathy index along with surgeons and CEOs. They have to be the sort of person who can calmly cut people open, fire them from their jobs, or blow them to bits if necessary.
I seriously don't much care about a leader's sense of decency. Trump cheats on his wife? So what? So did JFK and Bill Clinton. There are FBI surveillance wiretaps of MLK saying shit far worse than Trump's "grab em by the *****" comment.
John Quincy Adams used to go swim buck ass naked in the Potomac. Was it indecent? Don't answer until you see his picture.
Some things can't be unseen!