Not exactly a "gotcha" if that's what you're going for, FF as a series is expansive. Which is also why from the outside of that perspective, using examples largely specific to spinoff titles releasing during XIV's lifetime as your precedent reads as obsessive rather than constructive, especially given that Drain magic/Blood Weapon skills are more iconic to the Dark Knight across its history.
It wasn't meant to be a gotcha, it just clears things up and why you think I'm talking in circles. Simply because you keep talking about how it can't be tank when in fact, if you played it you'd know it can and more if you wish it.

I'm mainly using Bravely because it has the most expansive Dark Knights, 3 games worth while FF only has 2 and only one is worth mentioning. Besides, the point simply was that I understand the direction they went with XIV's DRK. It's a heavily armored relentless magic knight, the idea shows in Bravely and in FFXIV. Sometimes the reasons speak for themselves but you keep saying no for some reason.