This principle states that an ‘ethnic’ restaurant offering foods of two nearby countries will always be operated by people from the less-well-known of the two. Thus, “Indian and Bangladeshi Food” means an Indian restaurant operated by Bangladeshis and “Mexican and Salvadoran Food” means Salvadorans running a restaurant that may or may not serve Mexican food.

No Indian is going to say their restaurant serves Bangladeshi food, but the inverse is true because, they correctly assume, no one in the US knows what Bangladeshi food is.