I don't see PVP players complaining that they can't get rare sparrows to upgrade to legendaries because it's PVE only. I don't see them complaining that they can't get easier rep either through PVE specific modes like Tiger-Strikes or Patrol Bounties, which are obviously quicker. All this is proving is that PVE has things specific to it, just like PVP. If you want PVP specific rewards, guess what you have to do? And yes they are PVP specific if you have to have crucible marks for them.