They can't think that highly of the role's fun factor given that they barely play it
It's a time old classic post and IMO you're reading far too much into it. These comments generally boil down to 'make healers impossible to mess up on so I never have to worry about them letting me die'. It has nothing to do with actual fun outside of their own on an entirely different role. FFXIV has this wild and wacky aversion to failure at any level of content remember.
In my humble opinion, this is only an issue because SE have brought it on themselves precisely by balancing to the absolute bottom for years now. ARR on release was impeccably tuned and balanced and had a fantastic difficulty curve that steadily ramped up from AV, through the expert dungeons, into HM primals and onto Coil, even Alliance sat neatly in line. In essence, ARR had midcore content because it had a smooth curve that lead up out from leveling dungeons and into the endgame.Same problem. Balance for the middle and the lower half that can clear content now no longer will be able to, thus leading to them being harmed/bothered.
It doesn't work unless you balance to the bottom.
It was very possible to wipe in an expert dungeon, never mind a HM primal, people got used to it and as such, it was less of a problem, more people were happier to dust themselves off and put a bit more effort in. You saw that going into Titan HM where people would pool together huge shells that could field multiple teams capable of clearing it all night long to help those that were struggling (I refuse to believe that Ragnarok was alone on this, I had like 4 full linkshells and people were still had to be asked to leave once they had all their weapons and weren't up for helping others to make more room).
Now we're in this weird state where it's actually kind of challenging to wipe outside of Extremes but on the rare occasion that it does happen, people lose their minds.
I'm not saying that we need to return to the days of FFXI, but you yourself have commented that we have no midcore content so you're clearly aware of that problem. Where is that midcore content? It vanished into the casual mire when it all got tuned to the bottom of course.
If we want midcore content, the difficulty has to start somewhere, it doesn't need to be a steep curve and it certainly doesn't want to be a wall. It just needs to be a ramp that starts from somewhere like Alliance and needs to be tuned just a little above the bottom to wake people up and get them watching their screens again.