I think Sam nails it. So call conservatives are acting like that clinton supporter who started to complain about a military fly-by at the inaugeration, then said, "Wait a minute! Those are OUR jets now!"
Some support this funding because, to use Cincinatus' Wife's words: "He is the leader of the United States and is shepherding us through a very dangerous period of our history. If he has to fund programs (which I might add are nicely tweaked to seed conservative goals) then that is what he must do to continue the leadership role he has assumed to protect and defend the country." How funding tribal dances helps shepherd us through a dangerous period is not defined...But any criticism is seen as a betrayel. However, I didn't donate money to GWB's campaign so the NEA & Ed Department would get bigger. I think I can point out his betrayel of conservative principles without endangering the war on terror - which, as a military officer, I consider myself a part of.
Others, as Sam noted, defend this funding because, "At least the art isn't as liberal as it used to be". In their world, funding liberal art = bad. Funding conservative art = good. They entirely miss the possibility that funding 'art' is always a bad idea. It is bad because government funded art is usually awful, and it is bad because our constitution gives no role to the government in funding art projects.
It is stunning to see how many conservatives do not understand limited government!