Let's not forget the Muslim American vote has a role in this too.
While I'm not sure how many Asians are Muslims, and IIRC most Muslim Americans are actually black Americans, the fact that they went from voting something like 90% for George W. Bush in 2000 to some 85% for John Kerry in 2004 sure hasn't helped the GOP.
Turks, Kurds, Iranians, and Arabs are generally considered white.
What this means is that the only major group of Muslims who check "Asian" on the census form are those of South Asian descent. I would be shocked if the proportion of Asian-Americans who are Muslim exceeded 5%.