I don't think it's that inaccessible, but I wonder how much I have been 'trained' to understand modern speculative fiction by having consumed a lot of it and followed its progression. Maybe if you haven't read Anne McCaffrey and Katherine Kurtz, it's hard to absorb The Fifth Season. But again, I don't think it's that hard to take in, even if the world and reality is very different from our own.
In fact, it's so different that I'm somewhat surprised so many people think the book has some trenchant relevance to discussions of climate and race. I mean, surely it's there - persecution and control, and largescale climate effects on an entire world - but apart from very loose analogies, it doesn't seem very applicable.
The story itself is interesting and engaging as you learn more about the world, and its characters. But... not enough for me to go on for a whole trilogy. Another common complaint in the book club (and a merited one) is the choice of a first book of a trilogy.