There are a lot of like-minded individuals out there who think (properly, I might add) that you only "need" on things that you actually ... need ... hence the roll type itself being appropriately titled... Pass when someone else in your group has the corresponding main-spec for an item, then greed everything else.
To limit your exposure to loot ninjas, I suggest joining/starting a guild. Sure, it will take a bit of time to get up and going, but once you start running content and don't have to worry about loot distribution, you'll be glad you did it. From that point on, you'll be running fp/op content with people who won't need-roll for companions/off-spec/GTN.