Given that the same people currently celebrating what Ion said spent months trying to ignore what he said in 2018, or calling him an idiot, the sheer level of hypocrisy on display at the moment is illuminating.
As for the line regarding a different relationship with magic and the sunwell, that one was quite vague and open to interpretation. After all, one valid interpretation is that the different relationship with magic refers to the philosophical split over how to deal with their addiction and the loss of the sunwell which precipitated the schism.
Supplementary evidence is as follows to confirm this interpretation.
Blood and honor confirms the Sunwell has no limits. You don't need to visit it, it simply is. So long as it exists it's radiance transcends time, space and even reality to sustain all thalassian elves.
In the Shadow of the Sun confirmed high elven exiles can still feel the Sunwell, and they can feel it's difference. This was from an exile priestess who admitted she could feel it upon it's restoration but who only learned the fact of it's restoration upon Kael'thas confirming it had happened.
Cataclysm showed both Blood Elves and exiles visiting the Sunwell in pilgrimage.
All canonical sources emphasising that high elves and Blood Elves share the same connection to the sunwell, fully consistent with what Ion said.
The only thalassian elves who probably are cut off from the Sunwell are the Void Elves, given that, canonically, mixing a light based energy sourced with a void based physiology would probably lead to spectacularly bad results. Void Elves likely sate their addiction through a direct connection to the void.
The Mangas are of dubious canonicity. Some maybe true, some definitely aren't, but none can be relied upon. As an example, the 'Crusader's Blood' manga tells the tale of an innkeeper in Brill during classic, an undead, who tells a captive dwarf a story about a Scarlet Crusade Commander whose thirst for vengeance against the Forsaken leads her to take worse and worse actions until eventually, Sylvanas herself comes to put her down with Varimathras. The sting in the tale is that the innkeeper WAS the the commander, raised into undeath by Sylvanas as the Forsaken she so loathed.
Except..that's not possible. Sylvanas only gained the capacity to raise new Forsaken following the fall of the lich king and her bargain with the val'kyr. This means the story cannot be canonical. Quel'Danil's apparent aversion to magic is sourced from the Warrior
ivided and Warrior :United mangas. I don't believe it has been mentioned or explored anywhere else. Frankly Quel'Danil is too minor a settlement in too remote an area to truly examine whether they even have this philosophy. Even if they did, their size and remoteness renders them irrelevant.