My dad’s side of the family is Filipino, and my grandmother lived through WWII (She was still in the Philippines when the Japanese were there). A lot of older Filipinos hate the Japanese due to the occupation, as well as the things they did there.
However, the Chinese are often looked up to, because they tend to be merchants with money. My grandmother said of my older brother’s wife when she met her “she’s too Korean”. Which is funny since my sister in law doesn’t look at all Korean, and she’s as “whitewashed” as you can get. But then again, my grandmother thinks my mother (white) married my dad for his money (he’s a federal employee – what money?), and that he should have married a Filipina.
Obviously with older generations this becomes less and less true. But my mother is still very old school and alot of this does ring true from her perspective. She warned me about playing with Vietnamese kids when I was smaller because as she stated, they would just try to kill me later.
The one thing I still do see is some anger between Hmong and Laotians. Sure the vast majority get along great. But get two weirdos together and they are gonna fight just for that difference.
You mentioned the conflict between Honduras & El Salvador, but you forget the The Soccer War they fought back in 1969. AFIAK, Brazil & Argentina may have their soccer rivilries, but not to the point of going to war with each other.