When you que for a roulette you open yourself up to the possibility of non-preferred dungeons.
Leaving a roulette because "I didn't want to do x/y/z dungeon" is like throwing a tantrum because you didn't get the Christmas present you wanted last year.
You're old enough to know things don't go your way and you should be ready to accept that, but you still didn't think about anyone else and ruined their time as well.
With tank que comes tank responsibility. You're the instance leader the moment you que as a tank and screwing nine other people because "ungh this dungeon takes to long to clear"is not something you can argue will ever be justified.