It is literally always used as an insult unless you're praising them for their chivalry. When you call people white knights, you're calling them blind contrarians. Yes, that is very much an insult. Don't lie about it. Either own the fact you're insulting people or stop insulting people. You VERY CLEARLY don't mean it as a positive or praise.
VERY few people are saying the game is perfect. They're saying the hyperbole is just that, over the top hyperbole, and they're pointing out the good parts of the game and measured changes needed to improve it.
People who want to be mad and salty also want the illusion that they are an unchallenged majority. Many also want to bring other people down to their level to join them - "Misery loves company...even if it has to make it." This, they think, improves their chances of getting the changes they want. It also means they will attack and attempt to run off or silence dissenting voices, since that breaks the illusion that their positions are universal and unchallenged, and those voices of dissent would imply they need to compromise and reach neutral ground with those they disagree with, something they very much don't want to do.
So they get into personal attacks to try and drive off those people and/or silence them. Ironically, these are the same people that will defend their toxicity as "well, we've just been ignored and silenced, so that makes what we're doing understandable and okay".
As a long time Healer both here and in other games, the Healer ROLE isn't the problem. Encounter design and the Tank and DPS roles being arguably OP with heals and mitigation is. Homogenization is, but that extends well beyond the Healer role. The big issue that no one wants to talk about is the battle system is super rigid with Jobs/Roles supposedly having very rigid places in it, but then you get ones that blur the lines (like RDM) in ways that break the delicate balance that the rigid system is pushing for
In a game with a less rigid system, this would be fantastic. But in one with a rigid system, it makes some roles or mechanics broken or trivial or unnecessary or etc. The thing is, it's unclear if FFXIV can change from that rigidity. And that rigidity is what has driven things to the point they're at now.
The irony is, whenever someone points this out - ACTUAL criticism/feedback - they are attacked as the negative mob assures itself all that the game needs are some Healer Job changes to make Healer Jobs play more like DPS Jobs. Even when that has nothing to do with the things they use as proof to support it. Healer Jobs having more DPS buttons, for example, wouldn't prevent a TOP 0 Healer clear from happening again.
I honestly think it's because they tried to do too much all at once, and so it made the story feel disjointed. Doing the Ala Mhigo and Doma stories at the same time back and forth, but they were TOO separate, and frankly, the Ala Mhigo side got MUCH LESS share than it needed to have. We still can't go to Ala Mhigo city, proper. And if they were trying to do a "World is on fire overthrowing the Garleans from all fronts", then they should have had more than just "...in these two places". Bozja (an expansion later as side content) and Dalmasca (largely "off-screen" and only touched upon in the optional 24 man raid side content) could have given that feeling a lot more narrative strength.
It all came together in the patches, but it left the base expansion MSQ feeling kind of meh, and a lot of people also didn't like Saturday Morning Cartoon Villain Zenos (you fight him several times and each is "you have to beat him or the mission fails, but when you win, we just have him beat you anyway - until the 8 man Trial where he merges with a Primal super-dragon: THEN you can beat him easily" goofiness), so that didn't help.
BUT, it did a lot of world building which was necessary and paid off in both ShB and EW. So it has to be viewed in that context.
Thing is, at the time, it had plenty of good. Despite complaints, Eureka wasn't TERRIBLE even then, and the Ivalice raid series is probably to this day the single most praised one in the game's entire history. Come to think of it, so is the Omega series alongside Eden. It also gave us both an Exploration Zone AND Deep Dungeon (the only expansion to date to do so), four entire zones of said Exploration Zone instead of Bozja's two with a third that was planned but dropped due to pandemic constraints, and fairly good overall (OVERALL) Job balance, with some memorable battle content like Kuja and the Yotsuyu Trial, as well as the side content Yojimbo fight from the Hildebrand quest series. It was the single most packed expansion to date in FFXIV's history, I think, in terms of what all it brought to the game in sheer volume of content, and much of tht WAS praised either at the time or in retrospect after the fact.