So whereas a "Karen" would be a conservative White woman who weaponizes race against BIPOC folks, a "Heather" would be her left-wing counterpart...a White woman who virtue-signals obnoxiously, to "prove" how "antiracist" she can be by devoting her life to calling out other White people (and men) for performative purposes.

If you've ever seen the 1980s movie "Heathers" with Wynonna Rider -- it will make a lot more sense!