They made a mistake during release of Exile and hadn’t corrected it. Much to the point the “tank” dreads are still on the store image for Exile.
Not sure about the logistics of this as to why they can’t patch it in, but it was left as the Elder dreadlocks ever since. You’d think when they noticed (and they have noticed) they’d have put out something like a “free DLC” to get it in people’s hands or had it unlocked. Or somebody would’ve updated to the storefronts.
Frankly locking it to level 500 is bullshit since the people who paid for Exile clearly are expecting the associated store image to be reflective of what they’re buying. Especially seeing as now it IS in the game and nobody has it unlocked. At 500 it is free, but you are asking for a significant time sink potentially passed the point the player may be interacting with the title. What’s more is that we all clearly expected to have it unlocked with Exile, and yet it’s not. Regardless of being able to unlock it, it wasn’t in the actual pack as displayed.