You're not getting shafted. People play for different reasons. Maybe the other tanks only did those fights for vanity drops. It's not fair to tell them they're not allowed to roll for loot when they're unlucky enough to get grouped with you.

If you were doing those fights only for vanity gear, how would you like it if you kept getting paired up with tanks who told you that you can't roll on stuff you want? You'd get sick of it and not want to play.

Sucks that you had bad luck, but the tanks didn't do anything wrong. That's just how RNG is in MMOs. Sometimes you get what you want the first time, and sometimes you don't. If you're burned out on RNG to the point where you resent other players getting loot, it's time for a break.