Definition of "Can't Wrestle"

So what exactly do people mean when they say someone can't wrestle? Because I see different comments on videos and posts that always say "x can't wrestle" when the person can clearly wrestle. Certain guys get tagged with the "can't wrestle" moniker when they can work a match. If they are botching a moves daily, sure they are a bad wrestler. If they aren't putting on exciting matches, they are a boring wrestler. But I would just say those two things: boring or bad. I wouldn't say they can't wrestle. Guys like Baron or Big Cass aren't exiciting to watch in the ring, but their actual in-ring talent is average to slightly below. They aren't Khali though. I don't know, maybe I'm the stupid one, but could someone explain to me why wrestlers who are just average are described as not having the ability to wrestle?