The painting contains the following words and phrases:

Why did you rich capitalists only protest those racial policies that
added to the costs of doing business?

labor exploitation   

job reservation  

boycotts
influx control    

migrant labor

You created a system where you had the power, privilege, capital and
opportunity, while were were the victims of discrimination and
exploitation.

pass system    

white unions    

racial capitalism

wage discrimination 

monopoly ownership of natural resources

Being black I was prohibited from doing most skilled labor; job
reservation was only for you.

strikes 

homeland policies

division of labor