Wow, for a post with such an inflammatory title this was a very, very interesting read. A few thoughts....

(S)he mentions the dichotomy of casual vs. hardcore in the beginning, and what I find so paradoxical about FFXIV is that an end-game MMO can't really be "casual" when compared to any single player game, yet the developers clearly design the game so that you can spend as little or as much time PER DAY/WEEK as you want in the game. But what's interesting is, even if you play casually, say 10 hours a week, if you end up sticking with the game long enough to get to the level cap, unlock most/all of the dungeons and enter the end game, chances are you've spent many weeks getting to this point. If you stick with the game for a year and follow the content updates casually, at 10 hours a week you've put in 520 hours into the game after a year. For literally any single player game, that is a fucking SHIT TON of time (and this is time spent in the mmo for a "casual", more hardcore players will be up in the 1000s of hours). Even for huge games like skyrim, I spent a little over 500 hours and by that point had exhausted every piece of content in that game.

So what I'm trying to say is that there really is no truly "casual" audience, it's really just an illusion (albeit, a wonderfully convenient one for those of us who attempt to have a life outside of Eorzea) that the developers have creatively designed into the game. Anyone who's really delved into what the end game has to offer could be considered "hardcore" when compared to basically any non-MMO game (so it is relative as the OP mentioned).

So where does that leave "casual vs. hardcore"? Well, seeing as everyone is really just some level of kinda serious to really serious in the end game, I think a lot of these petty debates are really just a by-product of people living in a virtual world where you can't see someone's face or hear their voice (particularly in pug content where you probably aren't voice chatting) and therefore are far less likely to empathize with differing views/playstyles, as well as isolated examples of some people not understanding some of the unspoken nuances of various grouping/social tools in the game. To put it differently, it's when someone uses DF/PF or an FC/LS group with unrealistic expectations. DF is like a roulette, you must be prepared to get whatever is handed to you, but some people can't handle the RNG and will take out their rage through inflection-less text directed at an artificial avatar, because politeness is often spurred on by the non-verbal cues which makes up way over half of face-to-face communication. PF, at least on NA servers, is sort of like a dating website. You have a little more control over what you pick but you still have a lot of sifting to do to get anything decent, and people who feel entitled to PF carries like what OP mentioned need a reality check. It goes the other way around too, those expecting that just because they put "experienced only" in a PF description doesn't automatically induce amazing group synergy, even if all the players are individually skilled. Eventually most people learn that to get anything done, you have to simply not be a dick, and have some patience with sifting through the PFs and FCs until you find some like-minded people who will work with you to get shit done at a similar pace. Very much like RL in that sense.

The only truly "easy" content in the end game is light party dungeons, IMO, and in a way these seem like a reprieve from the rest of the excellently designed battles. Even 24 man raids are pretty intense, they're just designed so that there are so many people joining that it's statistically unlikely to get a group without at least a handful of people that can carry the less experienced ones. And honestly, that's really fucking cool game design, because as much as the experienced players love to complain about carrying those 24-mans, it's secretly a huge ego boost (and isn't that what video games do best...give us a sense of power and control?)

So anyway, maybe one day we'll get to play MMOs Sword Art Online style (except, ya know, without the whole "you can't escape" thing) and it'll just generally be easier for people to be sympathetic to other's differences when they actually meet "face to face".