I would say that's pretty hard (i.e. impossible) to reasonably distinguish between "discussion about an author" and "discussion of a biography about the author." The biography/biopic is just another source of information for on-topic questions about an author, and it's reasonable to question the accuracy or content of a biography.
Stepping back a bit, it's sometimes hard to analyze individual works, series or SF trends without talking about the point-of-view, ideas, biases, competencies, etc. of an author. Sometimes even the editor, like John W. Campbell, can reasonably be part of the analysis. So creators of SF themselves obviously must be on-topic.
In this particular question, it's about far more than some random biographical detail such as his marital status; it has to do with the creation of the Qenya language which is obviously relevant to Lord of the Rings.