Many Indians have internalized racism - looking down on their own kind. So marrying a woman from the dominant race gives them a leg up in society, so to speak. Plus the association of skin colour with social status is so ingrained in Indian culture, even for 3rd and 4th generation Indians here, that any lightening of their progeny's skin tone is viewed as a positive. Just see how many Indian ministers in the cabinet have married outside their race. (Shan's mistress that led to his divorce is Chinese, by the way.)
Malays also value lighter skin color, but religion reigns supreme and most have been raised with the Islamic notion of universal brotherhood (under Islam, of course). So marrying outside the race is OK - Indian, Chinese, ang moh - as long as the kafir converts. That's why you have so many DKK (Halimah Yacob), DKA (Ahmand Mattar), Chinese mualaf (now running all kinds of halal stalls selling Chinese food) in the community.