Reddit's definition seems more contextual, it weighs the dynamics of current economic, cultural, institutional, etc... racism
Here is the Oxford dictionary definition:
"The inability or refusal to recognize the rights, needs, dignity, or value of people of particular races or geographical origins. More widely, the devaluation of various traits of character or intelligence as ‘typical’ of particular peoples. The category of race may itself be challenged, as implying an inference from trivial superficial differences of appearance to allegedly significant underlying differences of nature; increasingly evolutionary evidence suggests that the dispersal of one original people into different geographical locations is a relatively recent and genetically insignificant matter."
Here is the Oxford dictionary definition:
"The inability or refusal to recognize the rights, needs, dignity, or value of people of particular races or geographical origins. More widely, the devaluation of various traits of character or intelligence as ‘typical’ of particular peoples. The category of race may itself be challenged, as implying an inference from trivial superficial differences of appearance to allegedly significant underlying differences of nature; increasingly evolutionary evidence suggests that the dispersal of one original people into different geographical locations is a relatively recent and genetically insignificant matter."