In 1950? That was true of all media, including novels written by women. Is Dagny Taggart the protagonist of Atlas Shrugged?
Back in the 50s? Most people of all kinds were, either implicitly or explicitly, even those who could have known and embraced better with a bit of context improvement.
Judging the people of the past by all the biases and ingrained assumptions of their time is myopic at best and a dumb path to disregarding a lot of wonderful knowledge too.
No human is free of at least some absurd ideas, it doesn't necessarily make the rest of what they create or say worth denigrating.
I'd hate to imagine all of us in the early 21st century only being mocked because of certain absurd things we surely take for granted as truths today.
Let me join you in acknowledging that I have been racist before. (And I might be again, if I slip up.)
The change of values throughout the years is not one of monotonically increasing moral rightness. Every age gets some things right, and some things wrong. So we should focus on the positive and not the negative, because that's what we would want done for us.
There were some decent scifi authors at the time - not least, Ursula K LeGuin.
Le Guin, while a great author, was 12 when the first Susan Calvin story was published, and wouldn't be published herself until 18 years later. So she wasn't exactly being overlooked at the time.
And if you really insist on some identity politics in your science fiction, you'd do well to remember that in 1941 Asimov wasn't a White man. He was Jewish, which while not as bad as being Black had some very real consequences in 1940s America, not least being subject to a university admissions quota.
I too eventually concluded it was Bayta since she was the one who figured out who The Mule was but the other characters contributed quite a lot.
Plus it's my belief that it was the intent of Asimov that nobody is actually a main character -- not for long anyway; I mean, people just die at the very least -- because Seldon's plan is just that big.
But yeah, Bayta was a very likeable character. One of the very few female characters that I liked from Asimov.
I suspect almost everyone has their own experience of „It happened to me!“: https://news.ycombinator.com/item?id=33295560