All of the reasons mentioned are exactly the answer. A 'Grip & Grin' is SOP in the world of statesmanship. At the very least we can be somewhat asured that the best interests of the USA are being brought to the table.
Many have stated this, or similar comments.
That, though true or debatable, has no bearing on whether it is truly sickening or not.
It is sickening to see the top official of a despotic dictatorial regime standing as equal to the President of the United States, the leader of the free world.
That is true even if the meeting somehow magically would solve any and every problem facing us.