Lets talk about the FFXIV player base..

[Nethereal]

FFXIV is a unique MMORPG IMO because of the way GCDs work and the nature of oGCDs. Disclaimer: I'm not a green dps but this is the true nature of FFXIV.

There's clearing content and then there's playing the correct way(MOAR DAMAGE). Anything that results in less damage over the total time frame of the encounter is the incorrect way to play this game.
Bosses in this game have enrage timers, the goal is to out race the enrage timer, doing things counter-productive to that point is playing incorrectly. Conversely required healing is never a damage loss and can be a damage gain if you have "free healing".

In many games second made decisions largely don't impact the overall outcome of a fight because they don't work on a strict GCD system like FFXIV and clipping if any is largely irrelevant. In FFXIV clipping is literally throwing away damage in an encounter. Every time you clip you eventually reach a point where you've wasted a GCDs worth of damage if not more that is damage that you will never get back in the fight until you wipe.

How many times have you wiped at a fight at 00.01%? That's literally any single GCD from anyone. I've wiped on Alex at 00.001% because the group was fucking up and I didn't reapply over my 15 Sec Dia and instead chose to glare and missed the window by a fraction of a second.

The above is largely only relevant to end game content but pretending that people who aren't playing correctly just because they're clearing irrelevant content is setting up the player base for failure from go.
You don't have to rub it in their face but if their individual play is taking up the parties time simply because they don't know any better people who like to pretend there are more than two ways to actually play this game are a bigger problem.

The last instance I did in crystal was with me tanking The Aery as a tank who as leveled every healer to 80 I pull based on what the classes can handle and then ease up if the healer is clearly struggling. This was not one of those cases, I died a total of 6 times before getting kicked. The WHM was level 58 and had not even done his second job quest and didn't have regen unlocked. No big deal they don't need regen. Wrong. Granted even if they had it they still would've failed. They said nothing throughout the entire run even as they let me die to single pack pulls(I had to clemency to get through single pack pulls as paladin) and every boss all the way up til the final boss. Their friend talked for them the entire time and when I finally initiated the vote kick the first thing they said to me after failing themselves(took 3 Crimson Prices in the exact same spot while standing still actually afk.), and their team was and I quote "If you don't like it you can get the fuck out." Needless to say I left Crystal.

In short if after a wipe you can mathematically tell that if there was hypothetically 8 of you playing at the exact same skill level in each role and you wouldn't be able to clear the content you're doing and you have no intentions of improving, stop wasting my time.