For me, part of it is honestly the principle of the thing. You named six different mechanics there. Add onto that all the ones you named that can't be easily avoided that's at least ten mechanics that just entirely break verisimilitude. Not to mention things like changes to how certain spells work, stealth, etc. I don't think these mechanics individually are all that problematic, as I've said before. Hell, I'm fully in favor of fast travel, I have no problems with it beyond Larian not even trying to give the teleportation circles in-game explanation when that would make them more interesting. But taken as a whole it all feels... sloppy and careless. Like they really don't care about the ruleset or consistency, and that sense of carelessness is gonna irk folks. Another aspect of it is that there are so many ways to give yourself advantages that it reaches a point where if you choose not to, then you start losing the satisfaction of playing the game. Because if you lose, it's not because you weren't good enough, it's because you're actively choosing not to use any of the many tools the game provides you with. You're not playing against the game anymore, you're playing against yourself.
And yet another thing to consider is that people care about the setting, and most of these mechanics break the setting for no other reason than because Larian thinks it'd be fun or funny. Even if they don't ever use the mechanics themselves, they know that the game world is fundamentally broken. It doesn't matter if they never use the mechanics, they know the mechanics are there and the world is shallower as a result because it allows for those mechanics.
