I think the real issue with some people is that that's an American tradition Obama explicitly does NOT want to follow. I don't think that part is accidental, or because Obama 'doesn't know any better', isn't aware of the grand American tradition. I think he thinks it's part of the problem, part of what gives America its reputation.
However, it would have been better had he got someone to show him how to bow correctly Japanese-style, if he was going to do that, but whatever. It's not really all that important. As a foreigner, you're not supposed to get it right; you get most of the points for trying.
I just love the way the Washington Times manages to be so ignorantly racist/nationalist/stupid, thoughy.