Looting rules.

[Crica]

if you want to be able to have the BEST possible chance to win gear in Duty Finder groups, play the class the gear is for, you know, LIKE THE LOOT RULES ARE SET UP FOR...

otherwise, form your own groups and use any loot rules you want to

[Kirschey]

I generally run Sastasha, Copperbell, and Tam-Tara on my 50 WHM since queues are instant. I roll need on the acolyte gear because I want it for my L16 ARN.
I don't want to sit in queue as a dps for 45min+ just to roll on the same gear.

Sure some people hit need when they don't actually "need" it, but it's a PUG. This is common. Don't get so upset about it. Maybe do some /shout groups with specific loot rules you like having set up.
I'm actually happy FF14 has this system in place, instead of other games where any class could roll on any item and you had to say in party chat "wait i need that" and just PRAY no one else would decide to take it for random reasons.