Original sentence: Racism is a belief or doctrine that differences in physical appearance between people (such as those upon which the concept of race is based) determine cultural or individual achievement, and usually involve the idea that one's own 'race' is superior
Edited sentence: Racism is a belief or doctrine that differences in physical appearance between people (such as those upon which the concept of race is based) determine cultural or individual achievement, and usually involve the idea that one's own 'race' is superior..  The real extent of racism is challenged by those who believe racism is used as a shield by those who seek to blame personal failings on others in a culture of "victimization"