I haven't looked at the data in your link, but since you're putting so much emphasis on the 2003 tax cuts and the wonders those did for the unemployment rate, I have to assume that the 2001 tax cuts did not do same wonders for the unemployment rate for 2001-2003.
So the question: what was so great about the 2003 tax cuts that was not so great about the 2001 tax cuts? Assuming no effects from the reckless bank lending that produced the housing bubble and no effects from the unsustainable military spending in that time?
2001 Tax cuts were passed June. Can you seriously not think of some strange event that happened that would have an opposing effect on Tax cuts.
It's not much, but it started the similar pattern. Passed in June, Topped in July, Started to decend in August.