Nah, he bowed. Not by much but he bowed.
Your defence of Obama is weak at best.
Are there not different levels of greetings in the American culture?
If someone were to see one relative greet their Aunt with a full tongue kiss that left her speechless and horribly insulted, would you then say ‘Well, one of her other nephews kissed her hello” when the other nephew gave her a peck on the cheek?
Of course not, because the two, while technically still “a kiss”, carry much more meaning due to the particulars involved.
What Nixon did was akin to a peck on the cheek, a polite and warm greeting. Obama frenched the old guy.
So yawn away, but if you can’t see that...