Your loot spec and current spec can be different. Make sure you have the right one selected. Does it matter though? With the exception of sub wanting daggers can’t both specs equip all the same things?
Different specs get different loot in broad strokes, like a DK who has their loot set to Frost will never get a 2H weapon in their vault.
It doesn’t mean you’ll get gear that is perfectly optimized for that spec.
Assassination and Subtlety both have identical loot tables, as they’re both dagger using Rogues. The only difference it makes for Rogues is whether you set it to Outlaw or not, because Outlaw uses different weapons.
Yeah but the game doesn’t give you loot based on stats. It gives you loot based on what you can use for that spec. For Sin and for Sub that’s leather gear, Agility-based or Melee-friendly trinkets, and daggers.