Im subscribed to Bannerlord (even tho I dont play it) on Reddit and its pretty telling that it does have a large amount of people who are very pleased with the game. At first I was boggled thinking they were some brain dead masses - but after reading their points of view it basically comes down to people who this is their first first exposure to a game like this
I think the main reason why so many people appear to be pleased with Bannerlord is the fact that the game does a fantastic job of tricking you into thinking it's way better than it actually is. I've played many games in my life, Warband included, and even I was successfully fooled by Bannerlord. Allow me to explain.
In the overwhelming majority of games features exist for a reason: to provide mechanical complexity, to balance some aspects, to increase immersion, etc. Bannerlord is not like this. It's a giant collection of worthless, barely working crap that exists for zero reason whatsoever.
"Wow, you can marry and have kids! Surely the game is designed around multi-generational play. Maybe not like CK2/3, but this system undoubtedly does at least something, right?"
"There are character traits! You can be a merciful lord or a devious rogue! Surely this means that characters with different traits behave differently and there are some unique interactions based on their personality, right?"
"You can own fiefs, this is so cool! I cannot wait to develop them into prosperous production, cultural or research centers! Surely towns and castles are more than just places to store your troops, right?"
"It looks like there's more than just waging war all the time, you can become a peaceful trader or a cunning rogue! Surely this means that these playstyles actually have any depth and provide you with unique opportunities?"
"The economy seems to be simulated to some degree! I cannot wait to wage economic war on my enemies and dominate them financially! Surely you can do this, right?"
As you play, you continue to encounter new mechanics and features like in these examples and you automatically assume that they actually mean something. Why would developers include them otherwise, right? Not only that, but you've played other games with similar features before, and most of the time these mechanics are implemented with at least some level of competence.
So you keep playing, but then it strikes you. The emperor has no clothes. Bannerlord is just a mess of useless crap that doesn't do anything. There majority of system within the game look like they are doing something, but in reality they could be removed in the next patch and the game would be largely unaffected.
Combine all this with the fact that Bannerlord is very grindy, especially for new players. Everything takes forever: grinding renown, money, skills, etc, so you need to invest a sizable chunk of your time until you fully realize how empty and hollow this game is.
I bet that the overwhelming majority of people posting positive reviews on Steam and Reddit are not stupid, they just haven't reached this moment of clarity yet.