Some of the complaints I've seen about The Last Jedi have a lot to do with the set up of the universe and the political situation, but I think that has a lot to do with the table-setting The Force Awakens did (or didn't do)
So, does everyone want to talk about the political state of the galaxy and why it is the way it is?
The opening crawl of The Force Awakens is really the place to start, as it set the tone for everything going forward in this era of Star Wars.
"Luke Skywalker has vanished. In his absence, the sinister FIRST ORDER has risen from the ashes of the Empire and will not rest until Skywalker, the last Jedi, has been destroyed."
Which, I think, says that the First Order doesn't come out into the open from the Unknown Regions until they knew Skywalker was on the run.
We know from a lot of the ancillary material (@ChuckWendig's wonderful Aftermath books, and other places) that Endor wasn't the decisive end to the Empire we thought it was.
Palpatine had a sort of Nero Decree called Operation: Cinder and that took a while to deal with (see Battlefront II, @ruckawriter's Shattered Empire) and the Empire made a last stand on Jakku about a year after Endor.
After the loss at Jakku (seriously, read Wendig's Empire's End and play it in BFII), the remnants of the Empire fled to the Unknown regions to lick their wounds.
In the meantime, the government of the New Republic was able to flourish. Mon Mothma spearheaded this and she created a situation where the capital wouldn't remain on Coruscant, but would rotate around the galaxy.
It started on her homeplanet of Chandrila and, at the time of The Force Awakens, it was located on Hosnian Prime.
With the threat of the First Order growing, a lot of people didn't necessarily believe it was a problem and there were a lot of centrists who thought the Republic should do nothing.
Maybe even just appease them. The Chancellor of the Republic that was killed by Starkiller base, seen here in the movie, was named VIllecham. (the "core name" of Neville Chamberlain, Nazi appeaser) 
The second paragraph of the TFA crawl explains: With the support of the REPUBLIC, General Leia Organa leads a brave RESISTANCE.
She is desperate to find her brother Luke and gain his help in restoring peace and justice to the galaxy.
She is desperate to find her brother Luke and gain his help in restoring peace and justice to the galaxy.
This is not an active support. Thanks to @claudiagray's Bloodline (written with input from @rianjohnson), Leia had been tossed out of the Senate for two reasons: one, plots against her from the FO, and two, the public discovers she's the daughter of Darth Vader.
The Republic has to offer a sort of tacit support. "Sure, if you think they're a problem, we won't let them destroy you or anything. You oppose them. Keep it quiet. Don't let anybody know we're working together."
These are the lies of the galaxy Hux refers to in his speech. They hate the Republic because the Republic is passively working against them. 
I think if I had ANY complaints about TFA is that JJ took a hard pass on dealing with the politics. Because like... three more seconds of this and the destruction of Hosnian Prime would have felt a lot more meaningful and desperate in the film.
The loss of Hosnian Prime is DEVASTATING for the galaxy, for the galaxy. Worse even than Alderaan. For one, every leader of every world was there for the session. Gone in the blink of an eye.
For two, and you can see it a little bit in the film, but ENTIRE Republic fleet is destroyed in the Starkiller blast.
This is why the opening of The Last Jedi is so devastating with the loss of the Bomber group. They need every ship they can get because the Republic isn't coming back. There's no one from the Republic to come help at all.
Yes, they kill Starkiller base, but that's a fraction of the might the First Order can levy against the galaxy.
It's no wonder Rian Johnson decided to start his story moments after The Force Awakens because there is so much turmoil in the galaxy AND for the Resistance that there's not really anywhere else to go until this phase of the story is resolved.
Then, let's move to what the opening crawl of The Force Awakens tells us. Because I don't think we've paid enough attention to what's happening with the First Order OFF screen. TLJ only tells the on-screen story of a sliver of their forces.
"The FIRST ORDER reigns. Having decimated the peaceful Republic, Supreme Leader Snoke now deploys the merciless legions to seize military control of the galaxy."
They are seizing control of the entire galaxy. This small contingent, led by Hux, is just to snuff out the Resistance. Snoke thinks everything else is a piece of cake, so he's here for this, too.
This is totally where I think the Knights of Ren still fit in. They're off commanding the smaller parts of the war. Taking control of Coruscant. Naboo. Bespin. Corellia.
JJ Abrams has a helluva stage to start Episode IX because of this table setting Rian Johnson has done.
SHOULD people have to read the books in order to understand the context? Not necessarily. And I was able to enjoy the movies just fine without knowing it. But there's enough in the movies to read between the lines if you look hard.
But Star Wars movies aren't "regular" movies anymore. It's expected that there will be ancillary material that sheds light on the consequences unseen in the films. And it's impossible to know what will be important until the last film in the Skywalker saga is out.
And for those who like these threads, be sure to tune in to @FullOfSith. This is pretty much all we do on the podcast.
