There are plenty of terms to call people out for shitty behavior.

Why use people's names? Names that belong to people we care about?

I know a Susan and a Karen. Both of them are warm, compassionate people. Both of them are also anti-racists and leftists.

Using people's names as an insult is mentally lazy.

I would also add this: I have only seen white people use these terms, either in person or on the Internet. Oh, my friends of color don't hold their mouths, but they would call someone a worthless bitch, a Fascist, or a drooling racist - something descriptive and useful.