*wheezes uncontrollably*
Of course, you would be this kind of person. Let me explain how your guide fails, point by point.

1: tanks have access to a ranged attack that gives more emnity/aggro than most skills, an AoE skill (combo in later levels) that can hit multiple enemies for aggro, a Provoke that puts them on top of an enemy's aggro list while giving aggro equal to a 2000 potency attack as well, and a Tank Mastery trait that makes tank stance give waaaaaay more aggro to everything. There's no reason why a tank shouldn't be able to pull off a dps anyways, especially since the "you pull you tank" mentality is considered griefing, which is potentially banworthy, iirc.
2: see point 1.
3: there are some instances where you don't want to kill the add, such as the Minotaur boss in Fractal Continuum, or the special Faust in A9 normal where he must die at a specific point. Hell, A4S has to deal with the Faust minions in a specific way, or they wipe.
4: this is true to an extent. There are some, keyword SOME, mechanics you can ignore or avoid completely depending on your ilvl, or if you run it unsynced.
5: maybe the person was typing out mechanics for someone during the duty, it happens more often than you think.
6: you do have a point, but not all attacks can be avoided, and some people's latency might cause them to be hit by an attack, even when it looked like they avoided it. Plus, in some cases, people have been pulled into the avoidable stuff by a healer's Rescue either by accident or trolling.
7: that lol dragoon move some jobs have? Can be useful for avoiding AoEs, and in the case of SAM and RDM, they deal damage as well, so there's no harm in doing it. Just practice using it so you have an idea of how far it sends you.
8: Crystal is not as bad as you claim. Yea, they're more known for RP, mostly because Balmung and Mateus are so open bout it, but that doesn't mean they can't actually raid and do high end content like other DCs. You just gotta put yourself out there and be willing to learn with others. And Aether might have "elitists" as you call them, but every server has them too, you just gotta find them.

Also, for point 8, YOU'RE ON GODDAMN BALMUNG YOURSELF, YOU CLOWN.