Sexism is the act of looking down upon someone for their sex
WOMEN CAN BE SEXIST
Racism is the act of looking down on people for their race
YOU CAN BE RACIST AGAINST WHITE PEOPLE [See Poland, Russia, France, !!!!!!!Balkan countries!!!!!!!, hell...
there is more to racism then just looking down on someone. Google systematic racism, institutionalized racism, and individual racism. The example you used is not racism, it is prejudice.