Well that was short! The White House is not using Youtube as its video player by default. It seems that now the videos playing on the White House official site are embedded in a Flash player provided by Akamai.
I think that both reasons above are valid, and a third one would be that Youtube has less broadcasting potential than Akamai. Remember during the Live Youtube event, Google relied on Akamai to support the heavy broadband requirements of the event. In other words, I think that the White House just cut the middle man to work directly with the source. Akamai is just more reliable than Youtube, and less spammy too.
Anyhow, for the Youtube community, nothing changes, as the videos will still be pushed to Youtube as they have been before. However, if Youtube is becoming secondary in the White House online video strategy, then the government online video strategists should consider using Tubemogul to push their content even farther down the long tail!