If that is what you want to accept then we will also accept white as
pure: unblemished, especially in character, purity; decency, decorum, delicacy; continence, chastity, honesty, virtue, modesty, vestal, virgin and black as the opposite. Those basic dictionary definitions are set up based on white supremacy so of course you will accept and believe that. They will alter everything to their advantage.
The truth is, that first definition is no different from prejudice: prej·u·dice noun (plural prej·u·dic·es)
1. opinion formed beforehand: a preformed opinion, usually an unfavorable one, based on insufficient knowledge, irrational feelings, or inaccurate stereotypes
2. the holding of ill-informed opinions: the holding of opinions that are formed beforehand on the basis of insufficient knowledge
3. irrational dislike of somebody: an unfounded hatred, fear, or mistrust of a person or group, especially one of a particular religion, ethnicity, nationality, or social status
4. LAW disadvantage or harm: disadvantage or harm caused to somebody or something
A powerless person can think with prejudice or what you call 'racism', but he or she is not really racist without power.
Your problem: you are going to a racist source for your definition. You're not going to get the truth with that.
It's like an elementry school student who goes to class and learns that Columbus and Lincoln are great men....but later on in high school (hopefully) or college they teach you that they weren't so great.
You are like that elementry school kid who is taking things on facee value. If you've taken any sociology courses in college you should have learned that racism deals with power.
'I'm not a sexist, don't have to power to be a racist, I'm a scientist, and an activist.'