Why do Cambodian people hate Vietnamese people?
It’s understandable. The Viets in Cambodia are like the Chinese in Vietnam. The immigrants dominate the business, take away jobs and look down on the locals. The Cambodians look at the Viets the same way the Viets feel about the Chinese in Vietnam. Now, if your gf’s family is sympathetic to the Khmer Rouge, it’s even worse because the Vietnamese Communist invaded Cambodia and overthrew the Khmer Rouge regime to stop the infamous Killing Field. Moreover, her folks might be very old fashioned just like a lot of old Viet folks, who only want their children to marry the fellow country people.