Personally, I think that's a bit much. I don't think he was being disrespectful. It's not like he was sitting down, or facing away from the flag.
The hand on heart thing, while traditional, is kind of antiquated generally speaking.
And on other occasions, he stood with hand on heart during the anthem.
If you see the video:
Urban Legends Reference Pages: Barack Obama and the National Anthem
You notice 2 things:
1- He's standing and (as pointed out in the article) his demeanor is quite respectable.
2- The rendition of the Star Spangled Banner is the reason everyone should be upset. Listen to it: HORRIBLE. And notice at the end of the song he turns, nods his head and claps approvingly.
If you watch the video, does anyone ...HONESTLY...think he's trying to be an anti-patriot? C'mon... He's a politician. He's got nothing to gain by coming of as disrespectful to the flag. The most important thing to any of the clowns is winning the election.
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But all that aside. One of the reasons this country is so great, is that one has the right to not stand, with hand on heart, during the anthem.