1. We need to also better separate optimistic boldness from "toxic positivity." See also below.
2. Yep. Not reading chat is pretty common in general, and it's also most likely going to be the case for the typical player (that's actually trying to clear the duty). Meanwhile, being toxic to the small segment that's actually there to grief is likely to give them exactly what they want. Flaming is a lose/lose.
3. This easily creates an also-toxic culture of fear, however, especially when you consider the side effects of being blacklisted. Somebody doesn't "get it" soon enough regarding raid culture (more likely in XIV, since in WoW or Lost Ark they'll understand all too well from being declined from group after group without even getting a chance to see if they perform well enough or not)? Next thing welp they have trouble falling back on even hunts or FATE/map groups or exploratories or even hanging out in Limsa because of having been BL'd due to gameplay issues in EX/Savage. They'd literally have to buy the game again to get out of this (and I'm not even sure if it would have to be a separate Square Enix Account, as I'm not sure if BL follows this or merely an individual subscription account).The only viable solution is for people to actively use the block/blacklist function a lot more. Only by denying entrance, they will perhaps understand that their behavior is bad.
4. It gets WORSE, really, because the role of Discord in all this almost permanently entrenches the power of the largest moderator cliques. Which means, it gets toxic and it doesn't implode, instead you mostly get people that accept empire or they evermore grumpily roll the dice on PF or quit the content altogether.
You need a big public Discord to make a difference (even big friendly guilds with endgame headcount in the hundreds usually need outside recruitment in order to successfully form a raid group, small as they seem to be). On top of the community management requirements this entails, or should entail, you have the Discord Trust and Safety team constantly breathing down your neck with automated enforcement measures that, based on numerous anecdata, are absurdly easy for just a single troll to bring down the whole house through if there is even a few minutes gap in moderator coverage. (This whole house can include the accounts of every member, too. Imagine trying to play without Discord, given that most active non-mainstream social platforms these days are, well, the kind that someone as stoic as Thancred would probably struggle to tolerate, much less be comfortable in)
The result is that most players (it mainly takes pure luck to avoid this) find themselves with a choice of rolling the dice on PF, or accepting the terms set by incumbent large Discord community moderators. Some are decent people, some are not, and unfortunately, the ones that are not probably understand all of the foregoing perfectly well enough to know they don't need to be, they essentially have a cornered market ...
5. Given the difficulties most games that accept such "but we have witnesses!" quantity based reporting have with abuse (right up to and including "stalking/grooming victim gets ignored because it's just one report, while someone that competed legit on the markets with an RMT cartel that ought not to be even getting to play in the first place gets banned by coordinated mass report" levels of absurdity) this is likely considered an intentional lesser-evil choice.
6. Yep. Duty Complete adds its own level of toxic and unhealthy, useful as it might be.
Start PF progging? Well you better death march that stuff because if you take a break and the others clear in the meanwhile, you can forget about continuing with them because they'll put up the Duty Complete wall so you're forced to put up "fresh prog" once more to actually get fills and your entire efforts have gone to waste, the way FFXIV mechanics work these days (in WoW this is more tolerable for various reasons).
7. I expect this is a fault of the FFXIV design and the way in which rez works, but there is no simple way around it (individual permadeath was tried up through Sephirot Ex and it doesn't really work in any useful way with a group of 8).
In most MMOs, when you die, unless you are a critical role worthy of using the extremely limited battle rez, that's it, you're hors de combat and either the group clears without your further input (in which case you clearly understand you got carried) or it does not (and then you clearly know where you stopped).
In XIV it gets muddied by raises, damage downs, healer LB3s - and even moreso by the fact that these (well, not damage downs, lol) are common and expected recovery methods in normal modes (some of which would in fact be fully as hard as EX/Savage if rez was limited similarly - just see WoW difficulty tuning for an easy example as the mechanics in WoW normal or even Heroic raids are often no more complex than a normal trial or alliance raid, but there you don't get to easily recover from KO the way you do here).
Unless you take those recovery methods off your bar during serious content (and there are Ultimates where the healer LB3 is required, so even that's a muddy spot) and the community just agrees to full wipe every time there's a player death in EX/Savage, this is always going to be at least something of an issue.