The attempt to redefine racism away from the dictionary definition into the "systemic privilege" one is, imo, an attempt to remove the intensely horrible associations with actual racism, to minimize its harms, and to provide a socially acceptable avenue for its practice.
Racism used to mean discrimination based on race. It's highly charged. People are trying to change the definition because they want that intense charge to be for something other than its original intent. And it's working! "Racist" is now a word getting robbed of its power.