Obama has proven to be singularly classless. It may be a cultural thing, though, and I mean this kindly. So often, the dominant culture (the dreaded Whitey) doesn’t clue in the minority population as to what is acceptable and what isn’t.
Obama’s crowd got kudos for snitching to the press during his campaign, so I guess he thought he could snitch out the President after a private briefing.
The press lauded his faux Presidential seal and his Greek columns, so he may not realize that his open disrespect for the current occupant of the WH, in sending reps to the G20, is boorish behavior.