A lot of it comes down to "what are you looking for from this game?" EW deliberately revolves around a lot of feel-good wish-fulfillment heroic fantasy - again, I do think the intent here was good, simply to "make players happy" - and really, that's probably exactly what a number of people are looking for when it comes to an MMORPG like this. They're there to have fun and enjoy escapism.
But, bluntly, when it comes to how expectations affect one's response to things - I probably wouldn't have been nearly as vocally disappointed in Endwalker if Shadowbringers hadn't surprised me, blown me away, and genuinely touched me in a lot of ways. Prior to Shadowbringers, I was a fan of FFXIV and had been playing and enjoying it for a while, but on a writing level, it usually amounted to "I can see the effort being put in here and it's fun to dissect on that level, but it's pretty clumsy more often than not." For example, the discussion a few pages ago with Hien and the Doma plotline - it's dumb and bad, I certainly discussed it being so among friends, but fundamentally it was also something I could mostly shrug and roll my eyes at, and move on.
Shadowbringers removed this possibility for me because it made me really care about this story and these characters, so when I saw them being mishandled, and being used to say things that both a) didn't fit within the moral framework the game had established prior, and b) didn't fit within my moral framework to an extreme, "shrug and roll my eyes" wasn't possible anymore. I know they are capable of much more, and much better, than feel-good shounen tropes and a rather self-serving "[x] character is good as long as they're our ally because we are indisputably good no matter what" and it became upsetting because falling back onto such things felt like a serious regression from Shadowbringers encouraging compassion and thoughtfulness. And because EW is a direct continuation and resolution to those ShB elements I treasured, I can't even compartmentalize the way they clash. So rather than shrugging it off, I opted to explode and thoroughly embarrass myself by ranting and raving on these forums, it seems. Whoops!
Also, it goes without saying that different people are going to have different reasons for disliking Endwalker. I disagree with tons of reasons people post here about why they didn't like it. Probably the majority of reasons, speaking numerically. I like Hermes, I like Zenos, I like G'raha, etc. I can't bring myself to get worked up over things like one-off comedy scenes or stuff like Tweetingway as a marketing device. It is what it is.