This is idiotic, do you avoid playing as a defender because the bubble is a massive crutch for that section?
A prevented wipe by a SS is a great use of an ult just like popping a bubble on that defense part is a great use of a defender ult.
You seem to imply that his team could not have beat that part at all rather then on that attempt without self res which is moronic. It simply saved them from wasting all the time of another thrall maze run in a way no other class could have.