Rocket Rob said:
Kissing a greeting and holding the hand of a frail old man are considered acts of equals and of friendship.
Bowing to a monarch signifies subservience to the throne.
Barack Obama is the first and only President to bow to a monarch
Your looking to far into this one bud. It was just a sign of respect. He probably didnt know how to show respect in that situation so he did what he though was right.