That's not bad story writing at all. Not everything needs to be explicitly shown to you especially in a situation where SE can't just make a special scene just because you happened to be going through the cut-scene on MNK. I was on SCH and I couldn't fight back at all so why should I be shafted because I wasn't on a class/job I haven't played since I reach 50 on it (and for some players haven't even leveled at all)? It's not fair or reasonable for one job to get special spotlight in the story.
And the way the scene finishes the brass blades walk up to you and you look over at Nanamo's corpse before the scene fades to black. That's the perfect set up for your character at least attempting to fight the brass blades. And then the scene when we are dragged into the Fragrant Chamber even hints even more at it. SE did as much as they could for players who would have wanted to fight back while also being fair to players who didn't or realized they couldn't. If you don't want to take what the gave you that's your prerogative but it's not poor story writing in the least.