Linguists don’t say varieties are right or wrong (even though they might have private aesthetic opinions like everyone else). That would be like a biologist saying dogs are the correct version of mammals and cats are wrong and/or don’t exist.
There do exist prescriptivist linguists, who do exactly that: they try to divine "correct" from "incorrect" usage of language.
Biologists actually say the opposite of that!
https://www.scientificamerican.com/article/cats-are-perfect-...