It's also Merriam-Webster, a descriptivist dictionary. Others are of a prescriptionist bent. For example, Cambridge: https://dictionary.cambridge.org/us/dictionary/english/retic...

More on prescriptive vs descriptive: https://twominenglish.com/prescriptivist-vs-descriptivist/

I personally am more descriptivist when it comes to English. It is also a lot of fun to bring some M-W citations in order to "Well, actually" someone who is "Well, actually"-ing.