That is a pretty wild definition of "racism" as "the idea that there are races."
But I kind of see how you got there.
The idea that human beings can be carved up along certain lines (demarcated by skin color and ancestry) and that there are significant differences between human capability across these dividing lines - and that justifies power differences and relationships of oppression between those groups -- those are the ideas behind racism, which expresses itself in oppression and injustice.
But the fact that people do carve up humanity along those lines, and therefore people find themselves put in these categories we call "races," and have different experiences and opportunities based on which one they find themselves in -- that's a fact. It's not racist to acknowledge it -- indeed, in a way, it would be racist to deny it because it would be denying the reality of oppression.
So "the idea that there are races" = "people are inherently and biologically divided up into 'black', 'white', etc and this indicates fundamental differences between them" -- that's racism
"the idea that there are races" = "there are 'races' because there are structures in the world which are built on the idea of 'races' having inherent biological differences, and these structures affect people" -- that's accurately recognizing that racism exists.
Does that make sense?
Does anybody have any idea how to evaluate Israel's claim that it wasn't them, that it was a Palestinian rocket towards Israel which went wrong and hit the hospital?
Other than just assuming that whatever side you don't like is lying?
I honestly don't have a heuristic to evaluate that other than "the side I trust less must be lying about it"
And I'd like a better way to find out the truth than that