Why does Miriam Mann keep removing the cafeteria sign? What does her act of defiance represent?

Miriam Mann was a member of back computer at NACA and in 1940 she removed the cafeteria sign that said "Colored computers" and put it into her purse. Days later, the signed appeared again but Miriam kept removing it to demonstrate her disagreement with the inequality and oppresion that these women faced in her jobs. The sign disappeared and was replaced several times until one day it was not replaced anymore. Her act of defiance is considered a small step towards achieving equality of black people. Chief officials at NACA understood the message that Miriam wanted to give and later removed the sign "colored" from bathrooms.