Your claim that the poster is calling certain groups inferior is entirely unwarranted. Please argue against the points they are actually making.
Edit: For examples, look at the various other replies that responded to the post without absurd speculation.
You are right about those more recent books though. I bought "The Long Way to a Small, Angry Planet" and "A Closed and Common Orbit" and was thoroughly disappointed.
Here is somebody, who has clearly great ideas - and is incapable of running with them, like Le Guin did. All problems, all conflict, all interestingness - is carved from the book like a diamond grinded down into a pearl. It always returns to what i would term "emotional pornography", a hugfest - very similar to what firefly became later on. I expect more from my scifi, a lot more, i rather have bad writting- which these books did not have at all.
They just dont go anywhere, like Le Guin did. So, while the parent is overgeneralizing, i think he is right here. The Nebula was undeserved in my opinion. If it must be for a woman, give it to Le Guin post mortem.
The specific claim that "she was pretty much forgotten outside of sci-fi readers for a long time" seems suspicious, considering she won a National Book Award in '73, was a finalist for a Pulizer in '97, and was declared a Library of Congress Living Legend in 2000. When was this period of forgetfulness?