In fact, I think "Karen" should be used if only to dissuade it becoming synonymous with "white woman, who I'd rather fuck off",

You have a problem with some one and passive aggressively try to make their life worse by getting them fired or calling the cops? Karen. Liz Lemon gets angry with you because your store has a policy that they don't take twenty dollar bills even though they are legal tender, and good for all debts public and private? Not a Karen.