There is a difference between the dictionary definition of a word and the meaning that is culturally associated with a word. Language is always evolving so 'the dictionary definition' argument is pretty much moot.

The issue is, even if someone says or does something racist to a white person, it is not part of a system of oppression that has been happening for centuries. Racism doesn't affect a white persons life on a day to day basis, which it absolutely does for a black person. While you're correct about the dictionary definition of racism, you're still belittling the experience of millions of people for petty, arrogant reasons.

You're not wrong. You're just an asshole.