As far as I know all dragons are just as sapient so using their bones is morally equivalent even if it is not a political tit for tat.
That said everyone involved in this is bar like a handful of elves is dead so there isn't much point to decide who has the high score for atrocities during the Golden Age or the War that followed it.
We're not talking about moral equivalence though. Volkirium is basically saying that Dwarves should shut up and not complain about some of them getting shaved for the Cloak of Beards because they use the corpses of dragons for their artifacts, but those dragons aren't from Ulthuan. It's like saying "these Dwarfs shouldn't complain about being killed by the Asur because they kill Druchii". Even if it's morally equivalent, there's a good reason for the Dwarfs to be mad at those Ulthuani elves regardless of the moral equivalence.
Also, there's another part to this argument that's not being addressed. With Dragons, the Dwarfs are killing them and harvesting their corpses. But the beard shaving could be viewed as even worse than that. It might seem weird when you first hear it, but follow me:
First, the implication is that these Elves shave the Dwarf and keep them alive so they can be humiliated instead of killing them. That, to me, is far worse than killing them and shaving their corpse. It means the Dwarf has to live with a shaved beard which almost certainly causes them to take the Slayer Oath, which is basically a long and elaborate way to kill someone while humiliating them and making the rest of their life living hell. This sounds dramatic, and part of it is the fault of Dwarf culture, but the Elves who do this are fully aware that these are the consequences of their actions and they choose to do it.
The Dwarves who harvest the corpses of Dragons don't delight in the process of torturing the Dragons. There's no point. They typically harvest dragons squatting in their Holds or who attack their holds because Dragons tend to like mountains and gold, and so do Dwarves. They like the weapons they get but there's no reason to torture the dragon to get it.
The Elves who shave beards aren't doing this for the protection of their homeland, they're doing it for a vendenta, and that makes it much worse. There's no reason to continously shave beards to add to the cloak, but they still do it.
I understand that this is a very small minority who do this, but the whole thing started because Volkirium said they shouldn't complain about being shaved because they use dragon materials. That's missing the fact that the process of shaving is very different than harvesting a corpse.
