Below is the exact quote from the U.S. census attempting to explain the logic behind the "race" ethnicity question on the U.S. census.

"The Census Bureau collects race data in accordance with guidelines provided by the U.S. Office of Management and Budget and these data are based on self-identification. The racial categories included in the census form generally reflect a social definition of race recognized in this country, and are not an attempt to define race biologically, anthropologically or genetically. In addition, it is recognized that the categories of the race item include racial and national origin or socio-cultural groups. People may choose to report more than one race to indicate their racial mixture, such as “American Indian and White.” People who identify their origin as Hispanic, Latino or Spanish may be of any race. In addition, it is recognized that the categories of the race item include both racial and national origin or socio-cultural groups. You may choose more than one race category." -census.gov

Apparently the department of redundancy department wrote that paragraph. Regardless, why is the word "race" not in quotes when they admit that they are not referring to the biological meaning of the word "race". 

Why does the U.S. government continue every 10 years with the inconsistency in the categories?

First they start with a color (white), which they say is not intended as a color but as a "racial-socio-cultural' group. If they don't intend the meaning of color, why are they using a word that defines a color on an official government form?

Next line is again color (black), continent-of-origin-nationality (African-American), and race (Negro).

European-American and Caucasian are not listed. Why?

All the other check boxes do not mention color (such as yellow or red) as a choice. Why?
Is is because over-simplifying a whole group of people into a false mono-color identity is offensive?

The other check boxes focus on continent of origin, nation of origin, territory of origin and ethnicity. Why?
Would it not be more helpful to know the education background of each family, regardless of their origins?
Or would that be offensive to collect? Does the U.S. care what is offensive to collect?

Here is more of the inconsistent information gathered from the "race" check boxes:

continent-of-origin and ethnicity (American Indian) 

location-of-origin and ethnicity (Alaska Native)

continent-of-origin and ethnicity (Asian Indian) Any "race" or color can be from India.

nation of origin (Japanese) Any "race" or color could be from Japan.

ethnicity-location-of-origin (Native Hawaiian)

nation of origin (Chinese) Any "race" or color could be from China.

nation of origin (Korean) Any "race" or color could be from Korea.

territory of origin (Guamanian or Chamorro) Any "race" or color could be from Gram or the Mariana Islands

nation of origin (Filipino) Any "race" or color could be from the Philippines. 

nation of origin (Vietnamese) Any "race" or color could be from Vietnam. 

territory of origin (Samoan) Any "race" or color could be from Samoa. 

other continent of origin (Other Asian) Any "race" or color could be from Asia.

other pacific island of origin (Other Pacific Islander) Any "race" or color could be from another Pacific Island.

some other race (Print race)

What does the U.S. really want to know? 

Why does the nation of origin not matter for European-Americans and Middle Easterners?

Why does the U.S. care about nation of origin for some groups and not for other groups?

Why does the U.S. use the outdated racial word "Negro" when on the same census they do not use the racial word "Caucasian" or the outdated racial word "Oriental"?