Why is it possible to create github authorization without oauthApp, but not reset/update?

Question

API

Using POST /authorizations with a body and BasicAuth, you can get a token and use it successfully. But only those registered on the OAuthApp github have the opportunity to get a new token for an existing authorization. As a result, the simplest crutch is to generate a note, thereby creating a new authorization every user login. Question 1: Why give the opportunity to create a new authorization through Basic, but not give the opportunity to update the authorization through the same Basic? Question 2: If github moves everyone to oauth, then why leave the documentation for creating authorization through Basic?
{ "note": "myApp" }

Answer 1

but do not give the opportunity to update the authorization through the same Basic?

Is such a possibility mentioned in rfc7617?
well, at least because of backward compatibility with legacy code