you know, there's actually more complexity here than we're talking about regarding handshakes.
You've got your two-handed handshake, your touch-the-elbow handshake, your pat-on-the-back handshake and even the 'bro hug' with handshake in between you. Which of these are appropriate between old men and young ladies?
Also with men shaking hands, it's always clear that we expect the webs of the thumbs to meet and to give a pretty good squeeze--some guys even to the point of hurting--but with women it's never clear. Don't want to hurt her, but don't want to snub her either.
I've heard women given the advice to close before the thumb-webs meet so they can squeeze the fingers of the man and not get their hand crushed. Actually a good plan sometimes. But some people are offended by this --it wouldn't be acceptable between men.
Another factor is the angle of the hand. If you've watched the Allan Pease TED talk about 'getting the upper hand" you'll realize that you show dominance/submissiveness by your hand position. You won't even realize you're doing it, but if you're trying to shake with you're hand on top, you're trying to dominate. Ref, recent hand battle between Carly Fiorina and Ted Cruz.
https://www.youtube.com/watch?v=I9WhadyyZ_E
But in some cultures if the woman offers her hand, she may be expecting to get the back of it kissed. Not doing that here.
So, yes, I'm glad that the leaders of first choose to congratulate people. However they choose, I'm glad I'm not deciding.