Well, it depends on who you ask. In general, there are two schools of thought when it comes to linguistics: prescriptivism and descriptivism.
Prescriptivists would say…
- language rules exist in an explicit form in a codified standard (“the norm”);
- people say utterances based on these codified rules;
- the correct form is determined by what the standard is;
- ergo, if a form is correct, native speakers should use it.
Descriptivists would say…
- language rules exist in an implicit form in subconsciousness of its users (“the usus”);
- people say utterances based on these subconscious rules;
- the correct form is determined by how people speak;
- ergo, if native speakers use a form, this form is correct.
So, in short, a prescriptivist would say that the first form doesn't follow the codified rules, thus, it is incorrect. On the other hand, a descriptivist would say that since the first one is used more often than the other one, it is a better description of the usus.
While the first line of thought (prescriptivism) might seem to you more down-to-earth and that's probably what you have been taught at school, the second one (descriptivism) is the one regarded more scientific in academic circles (and probably subscribed to by more professional linguists).
TLDR: a linguist will likely say it is correct (because a native said so), while a pedagogue will likely say it isn't. There is no common approach.