You're just cherry picking the argument you want to fight. Look I'll summarize what has been said between the three threads in the general forum and the last 8 years of FFXIV:
A) The Healer is meant to heal, both Yoshi-P and the game's own storyline and even this Hall of the newbie that I didn't even know existed until someone mentioned it say this over and over again:
The only time attacking as a healer even comes up is "When nobody is bleeding", which is something that again, only happens in F.A.T.E's not Dungeon play. Even in V1.0 the emphasis was on healing.
B) The game does not do a good job with it's AI companions, not only can you not "party" them, or other players pets, for the purposes of the tutorial, the game does something that you tend to only see in F.A.T.E's
That being, the AI characters act nothing like players, they stand in avoidable AOE's, all the well telling you to avoid it. Who else does this? Pets and mounts. You could be forgiven thinking that every AI character and monster in the game is exceptionally stupid. This is why "escort missions" are some of the most loathed game mechanics in all games, because the AI is just too dumb to avoid being hit, and is for all intents a pincushion. If SE is listening, how about making high level monsters and humanoids try to dodge player AOE's? How about making pets/companions dodge AOE's?
C) The game is turned based for all it tries to hide it. It is not an Action RPG, it's more entertaining than say SW:TOR (which is turned based, but has a decent storyline, far less dumb companion AI, just boring gameplay), and has outlasted dozens of other MMORPG try-hards that have otherwise better action elements and next to nothing for story.
If the game seriously wanted healers to primarily DPS and only heal 17% of the time like someone earlier in one of the threads mockingly suggested, all the healing would be HoT, and you'd have far more combat tools. That is not the case, everything but Stone has some application in a group battle. In a solo battle, the effects of stone let you keep your distance from the target. Assize, Aero III, Holy are meant to be used for their effects on a group. Repose and Fluid Aura are meant to be used on single targets
Aero II+Aero +Fluid Aura (to knock back the target)+Repose to put them to sleep while the DoT's tick down. While it's asleep heal yourself. When the mob wakes up, hit them with stone to slow them down, and repeat. Do people play this way? Not really, they would rather just tank single mobs. When in group play, you can't use Fluid Aura because it makes the Tank mad having to chase things, and you can't use Repose because the DPS will just keep shooting anyway from auto-attack.
D) If your skills are tools in a toolbox, use the right tools. I reject the argument that "you're not using all the tools", some of these tools are not useful, and counter-productive outside of solo play. Other tools were clearly designed for dungeon play and have no practical use in solo play because there are no crowd-control situations where this is useful (like really, who spam's Holy at a single mob?) At the beginning of V2.0 people used to use sleep effects all the time (in fact the RMT bots were very fond of it on THM, and it was a tell for those) now I never seen anyone use it because as I mentioned above, people won't stop shooting things that are sleeping. More to the point, name a boss that this actually works on. No the entire point of sleep was so you could take down a single target in a multi-target situation while you have no AOE's. If we were really arguing that you should use every tool in the tool box, everyone would still be using sleep and repose as their first tool, not discarding it once they get an AOE attack.
E) The internet spoils everything. So instead of finding the best strategy by yourself through trial and error, or maybe experience from other combat in the game, everyone is all to quick to cite whatever BiS gear and min-max DPS rotation as suggested by the tutorial/video instead of maybe figuring out better solutions or maybe what the developer's intent was. They give you 90 minutes to do a dungeon for a reason. If you can complete it in 12, or solo, that's because you are WAY overgeared for it.
Which brings me to the reason I mentioned 8-mans earlier. For all intents, as the game progresses, people have found ways of skipping entire sections of the game, found ways to use emergent gameplay (like bringing mobs to the cannons, instead of fighting them where they spawn like the developers intended) and SE has said nothing about it. This is another variation where people do things because that's what experience with that duty calls for. I can't tell you how frequently back in V2.0 players would spam these things for tomes, and all the newbies got steamrolled over not knowing why we were running mob trains. But clearly Yoshi-P has a problem with healers being "forced to DPS when they want to heal" by players claiming that the game mechanics require them to. It does not, and it has never.
F) There are players who will refuse to DPS, point blank, because that is not what they signed up for, they signed up to heal, not be a third DPS. Let them play it that way, because again the game does not require that. If you are after the Savage content, you form your own static to play it, because you're not going to train a PUG party, and if you want to farm something out of it, you're going to get stuck training every party that somehow forms after 5 hours. The Savage content also doesn't require you to DPS as a healer, but good luck getting a party together since everyone wants to rush these dungeons instead of learn them. Are you saving 10 seconds, 10 minutes, 30 minutes if you DPS? Who cares, clearly there are people who take the game too seriously and would rather waste time arguing and re-queing than just rolling with what they get in a PUG.
G) There are also healer players who just jump into cleric stance and do nothing but DPS. That's what they do in 8/24 man content because they can get away with it. They can't get away with that in 4-man content, and will get called on it because that "cleric stance" indicator says they aren't healing efficiently or at all. In 8-man and 24 man content, you can just ignore that unless the the lack of healing is causing wipes. Because of the amount of time required to start a raid, people are more likely to put up with a bad healer than they are going to put up with a bad DPS carry.
H) If the player skill mechanics are going to change and be simplified, then all advice out there needs to be thrown away with it. I would not be surprised if they (SE) changed the game mechanics so that everything people learned up to now doesn't work anymore.
Just look at the Red Mage skills descriptions. You are going to be told to do combos to save up for bigger booms . It's very likely the "lilies" for WHM is the same thing. You will be needing to do a fair amount more healing and don't get to do any large DPS booms without it.