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.
Yes there are many players that think the way we do but a common sense lootsystem will help those that does not understand how need/greed/pass works.
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.
To find/create a guild that runs all kinds of flashpoints at all times is almost impossible nowdays.
Groupfinder is still the easiest option to find players within the same levelrange.