While growing up quite a while ago, lol think way last century, the term always meant "someone who always looks at themselves in a mirror". IE the Homecoming Queen, the girls you dislike in 7th grade, movie stars, politician's wives, the cute boy in 8th grade who ignored you and thought he was such a hotshot.
Now it covers all the comment sections on SM, mean boyfriends, ex-husbands, nasty girlfriends, criminals, Chris Watts (according to some), Shan'ann Watts (according to others), commentators towards other commentators. It's basically the first thing said in a new case, and continues on and on.
I don't mean you or anyone else on WS, but that explains why I myself am just not going to decide who is and who isn't. And I've had lots of experience with mean sickos.