I said that without the possibility of PC deaths, there was no drama, no stakes, no tension. The GM is just telling a story, and the players are an audience.
So, why do you think that, without the possibility of death, the GM is just telling a story?
You seem to be linking the concept of PC mortality with PC decisions having impact on the narrative. Do you actually think that, if the PCs cannot die, the GM is personally determining all results in the game?