So about Summoner...

[xxPheNoMeNa]

I'll be using percentiles as a way to sum up increments of player skill as it is convenient

I'll answer this in bits since char limit

Does anyone actually believe people created this or other threads like this because they decided to complain randomly

Not randomly, but they make threads like this based on false pretenses and a very flawed justification by misusing parses in an attempt to "prove" their point. Making statements like "SMN is the 2nd highest dps in the game" when we can easily prove otherwise is why I have such a problem with threads like this (and even more so that people eat up that title and think it's truth). Maybe at the 50th percentile level of play that's true, but I don't think that's the skill range we should be looking at to make legitimate discussions about class balance no offense.

what about those groups that do Parse runs

This is far from your original point about party finders for PROGRESSION excluding classes that we deemed subpar. If a group is wishing to do parse runs, then they're going to want the best classes that allow them to do just that. There will always be an optimal comp in that aspect and people have to accept that. For the others however who are simply excluding classes for progression purposes (more specifically to the casual/midcore crowd, for hardcore prog composition will matter to a degree), or statics who just weekly clear, that's where the mentality issue shines. You don't need a meta comp just to clear content.

are they all in the 99% or is 90+ the 1%(where is the line drawn)

The line is drawn between those who actually attempt to optimize their game play in such a way where raid comp will actually matter. If you're attempting to legitimately speedrun, comp will matter. If you're attempting to do hardcore progression, comp will matter (to a degree, it's not as strict as speedrunning but you will definitely choose stronger classes for prog that offer clear advantages for the goal of clearing content easily and quickly). If you're doing parse runs then to some degree you also fall into this category. But that's really it. Raid comp does not matter for the sole sake of clearing content really, raid encounters are not tuned like Gordias.

when is it ok for the rest of the player base to be upset with balancing choices

When there's a legitimate case to be made for it. Like the beginning of stormblood when DRG/MCH/SMN/WAR and to a lesser degree BRD and BLM had obvious problems that were even further exposed at higher skill levels, those were balance changes that needed to happen. The recent changes to AST could be detrimental to the balance between healers because if AST actually replaces WHM in prog going forward, then you do have a legitimate case to be made for WHM. Before those changes though, WHM had a very clear advantage in prog. Saying SMN needs a nerf because it's "the best caster" is not a legitimate reason to me, not when DRG + NIN + BRD has been the holy trinity for years and has continued to be untouched while SMN is still struggling to break into that 4th spot. Not when RDM's "strength" is something that can't be shown in parse numbers but is still one of the most overpowered support utilities in the game.

they might be exaggerating but they are issues.

What are these issues? SMN's damage is not a real issue, BLM's damage is not really an issue (BLM is in a decent place right now, maybe they could use a very slight buff but as I said, they're extremely close to SMN with the utility SMN has factored in), people will just inevitably hate on BLM (and SAM) because it's a class that provides absolutely no utility and too many people are shortsighted and only think about what a class can provide to them personally. RDM is not really an issue considering the utility they currently have.

thats a valid desire for them to have and there isn't anything you, me or, anyone can say about that

Yes there is, its "get over it". Accept it because as I said, it's going to happen no matter what balance changes you make. There will always be an optimal comp to be found. Maybe SE will directly (or indirectly) nerf AST to the point where WHM finally has its time to shine outside of prog, but the same issue will be there only its AST sitting there. RDM will forever be a prog only job so long as it can verraise an entire party in 15 seconds. And honestly, I think it's perfectly fine for some classes to be favored for progression while others are favored for optimizing. The class has its use and it would be highly desired for that purpose. But beyond that, this exclusion that the community has towards those classes for anything outside of what I specifically labeled above, that's a mentality that just has to change among the players themselves (yet it probably won't)