Nobody in horror tells a new arrival that if they haven't read Oliver Onions or W.F. Harvey they aren't real fans
It's only SFF in which the genre's founding fathers (never the founding mothers) are used as clubs against new fans.
But even if there were such people, would the SFF gatekeepers listen? Probably not.
occurring in society," was not the sf these other sf writers wrote.
In the 1930s science fiction had a choice: to emphasize mainstream sf (the type in mainstream magazines) or embrace pulp sf (in the sf pulps).
Don't let people like Martin tell you what the history of your genre is.
We know (thanks to sales data) that the sf pulps sold very well in places like Harlem and Chicago's South Side. We know Black sf fans not only existed, but had clubs. We can be sure that a certain % of those fans wrote for the pulps
Received wisdom as propagated by the likes of Martin is that the genre was written by white men and a handful of white women.
Now, me, I think that there were plenty of Black (and Latinx and Asian) fans who submitted to the sf pulps, either under pseudonyms or their own names. I think a number of them were published.
I know of no easy way to find the facts about these authors. But we have their stories. They can be read & considered & analyzed. We can find queer themes in stories that eluded previous generations of readers, for example.
It's not. The history of sf is wide-open--undocumented--uncharted. Heavily white? Maybe. But just as likely to be populated with BIPOCs as just whites.