Why are east Asians preferred over south Asians by guys?

[Anonymous]

Lighter skin

Media promotion of them as cooler dating options

Others

[FoxnEagle]

That is certainly a geographical, societal, and personal preference. Also there are multiple aspects to it like body, cultural differences, and societal perception.
I am in New Mexico, I know a few friends who would like to have an east Asian lady, but many more love the darker skinned south Asian ladies. Here the societal preference leans more towards tan, olive, soft brown skin. There's also always going to be some people that don't like the oval face, love it, or are indifferent. Same with height.
Cultural differences certainly vary between the two. Out of the many transfer students I've interacted with over high school and college, east Asians were normally more shut in and normally had a bit of an adjusting period before they opened up. (As one of them told me, she was a bit overwhelmed with all the attention, informality, crassness, and how loud and boastful we are). Most of the South Asians fit right into the culture, with a few noticeable cultural differences regarding personal hygiene. (Had two Indian ladies who I don't think ever wore any kind of cologne or body odor suppressant. Was not a fun time when they were literally running late to class and came in sweaty...).
Lastly, societal perception. I'm going to make some obnoxious over-generalizations here, but there is truth to them. Weebs flock to east Asians assuming they know their favorite anime and want to be their friend, and ALL east Asians eat sushi. South Asians are generally assumed to be religious, and either part of Islam, Buddhism, or Hinduism (despite half of them that I've met being atheist, and one being Christian).

[Jamie05rhs]

They're not. (At least not in my book.)