Regardless of the occasion or circumstances, a presidential pronouncement is expected to be a rational imperative. It is framed to withstand the laws of logic, irrespective of the attitudes of individuals, or even collective groups, towards it.
Those who advise presidents, or otherwise participate in curating their public messages, do well to remember this. Communications from on high are likely to be fatally flawed if they are rendered in levity, or as miscellaneous self-exculpatory tirades. Anger communicates a huge sense of frustration.