I have Indian friends back in the US and I must say they have a very unique culture and diverse religions. They're mostly friendly but the way they do things is, shall I say, different. To me that was nothing and I took it as a difference in culture, not necessarily something bad, although at times it gets irritating if you're not used to it yet. I guess that's why some people are biased or "racist" towards others because of the difference in cultures - they can't accept the diversity and cannot live with other "types" of people, or worse, have had bad experience with them that they unnecessarily associate with the race/ethnicity.

I guess being around other Asians and other ethnicities (Vietnamese, Chinese, Cambodian, Caucasian, African-American, etc) gave me a broader outlook than I used to have before I migrated.

It's not that you shouldn't care, in fact you should - but you must learn that some people have had no exposure to other cultures or have been influenced by other people to throw derogatory remarks at other cultures so just leave them be, knowing you're in a better position not to make things worse.