Asians vote Democrat for precisely the same reason (and in similar proportions) as Jews do (vote Democrat, that is).
They all view Republicans as how Leftist caricatures portray.
Many of the asians I know, are Republican. It tends to differ based on country of origin. Japanese, Chinese and Koreans are hard working, more affluent, and tend to want to hold on to their money and not pay high taxes. Those tend to be conservative. Filipinos, pacific islanders, Thai, Vietnamese and other asians on lower economic rungs tend to be Democrats. My wife is Chinese-American, and her family and relatives are predominantly conservative. They tend to look down on Filipinos and others as not hard working; sounds racist of them and probably is, but that's the way it is because all asians are definitely not alike.