1. There is nothing imaginative about it. A child throwing out random ideas and copying cool scenes from TV shows at random is not "imaginative". It's made worse when every edgy social-commentary trope is forced in.
2. The biggest offense, of course, is the word "science" in her being labelled a "science fiction" author. A 4th grade understanding of the first chapter of a geology book that is immediately violated is not "science fiction".
Of course, I am mainly upset about the destruction of the Nebula Awards by the inclusion of the Fifth Season in the list among authors who actually understand science, computer science, served in the military, and overall have, and further, an understanding of how things work. Jemisin might be on par with that guy who wrote about magic balls catching lightning (Sanderson) in the Stormlight Archive, but neither of them belong on a good science fiction list.
On your first point, you have to at least acknowledge that a ton of people strongly disagree with you. I've certainly bounced off of widely read and highly rated novels before, but rarely do I leave with a complete dismissal of the quality of the work. It seems almost personal to you, calling a widely and multiply published author a "child throwing out random ideas".
On your second point: The Nebula Awards specifically target "science fiction" and "fantasy" genres. I'm quite widely read in science fiction. I took a look at the list of novels that have won or been finalists for the Nebula Awards. It turns out I've read quite a few of them, scattered over the decades the Nebulas have existed. The Fifth Season is far from the only set of books with fantastical elements to have won, and the ones I've read that have won have plenty of world building elements that would be incorrect by a fourth grade textbook (FTL? Reincarnation? Fire breathing dragons?). Yes, the Game of Thrones novels (a Song of Ice and Fire), though quite excellent, are quite firmly in the realm of fantasy, and they were often Nebula finalists! By your criteria, the Nebula Awards were "destroyed" a long time ago. Several books, including some from the very early years of the Nebula Awards, are now called "science fantasy", i.e. science fiction that leans into fantastical elements. The Fifth Season is actually typically labeled as "science fantasy".
If the Fifth Season "destroyed" the Nebula Awards, then you would see more recent winners being almost exclusively science fantasy. I haven't read as many of the newer winners as I have older winners, but two of my favorite novels of recent years won or were finalists: Network Effect by Martha Wells, which is pretty much a core science fiction novel, and Piranesi, by Susanna Clarke, which is even more fantastical than the Broken Earth.
One of my favorite recent-years science fiction novels, Children of Time, surprisingly didn't get a Nebula, but it did get a Hugo. Looking at its publishing year though, 2015, I see why! Three Body Problem was nominated, and Annihilation, which I absolutely adore (but can't spell), won that year.
I will acknowledge that people have tastes I don't understand - Children of Time was another collection of filler tripe that contributed nothing to the genre. Definitely put it down when I realized it's "A Deepness in the Sky", without the good parts, just "lol prehistory with spiders."
You brought up Martin - he has a passing understanding of history, combat, and was a veteran (aka is somewhat grounded in reality while writing fantasy), which is why Gemisin and Brandenson should not be used in the same sentence with him, and definitely not with Tolkien.
2. The biggest offense, of course, is the word "science" in her being labelled a "science fiction" author. A 4th grade understanding of the first chapter of a geology book that is immediately violated is not "science fiction".
Of course, I am mainly upset about the destruction of the Nebula Awards by the inclusion of the Fifth Season in the list among authors who actually understand science, computer science, served in the military, and overall have, and further, an understanding of how things work. Jemisin might be on par with that guy who wrote about magic balls catching lightning (Sanderson) in the Stormlight Archive, but neither of them belong on a good science fiction list.