But you shouldn’t retcon established lore (even if it is problematic) with a tweet.

That is not what happened: The change was already in the last edition of the codex from last year. Per the article…

But the most recent 10th-edition codex includes a point-of-view piece of lore from Calladayce Taurovalia Kesh, who uses she/her pronouns.

The tweet only highlighted a change that had already been made.