why did the phrase separate but equal become associated with the supreme court ruling against homer plessy

Plessy v. Ferguson was a landmark 1896 U.S. Supreme Court decision that upheld the constitutionality of racial segregation under the “separate but equal” doctrine. The case stemmed from an 1892 incident in which African American train passenger Homer Plessy refused to sit in a car for blacks.

Explanation:

i think its the outcome of people's preferences.

a social contract.

"a social contract is an agreement between citizens and their leader where the citizens give up certain freedoms in exchange for protection. the constitution of the united states is an example of a social contract."