I don't think this is a direct retort or agreement, but just something you prompted me to write down:
I think some of the seeming contradiction comes from an insufficiently specified rule definition.
If the rule was "walk through the fire when it's conditions are X, Y, and Z, but only if your goal is to become stronger on dimension X, otherwise never walk through the fire (insert other specifications here)", then we don't have a problem.
If the rule was fully-specified then you would know whether to walk through the fire or not.
If you have a rule that is insufficiently specified and you know it, then come up with your own rule or just assess the situation.
If you have a rule that is insufficiently specified and you don't know it, then you're outta luck.
If you have a rule that is sufficiently specified, but too complex to apply in real life, well that sucks, but I don't know what to do about that.
If you have a rule that is sufficiently specified, then hooray!
(I think it's likely most how-to-live-your-life rules are probably underspecified, but the downsides to that are low enough, and the upsides of less-complex rules are great enough that it's fine.)
alkjash writes about how following the rule 'walk through the fire' pretty much always makes one weaker if followed, so you should not follow it.
Isusr writes about how following the rule 'walk through the fire' can pretty consistently make one stronger if followed, so [given some preconditions, writes Isusr] you maybe should follow it.
This reads on the face of it like a deontic dilemma. Not all deontic-dilemmas-as-parsed-by-humans, just like not all questions-about-matters-of-fact-as-parsed-by-humans, can be dissolved. But I think this one can.
Don't walk-through-the-fire as a rule.
Walk through the fire in the sense that if you see a Fire that it looks like 'OH imma need to walk through that fire', WALK THROUGH IT.
In school, my brain was trained to associate [not-walking-through whatever flaming hoops those Evil Teachers laid out before me [homework, after-school activities, doublethink]] with the immediate feedback of Teacher disapproval, which triggered guilt. So my brain got in the habit of automatically walking-through-the-fire. You see something painful that it looks like you might feel guilty if you don't do? Do it. Don't ask questions about how it will help you. Ha ha. The Evil Teachers are in control. And the rule worked, back then, because they were.
Later, I got free of the teachers. I realized that the person I had been, following that rule, was insane. I learned to love-things, care-about-things, reach-for-things, independently of whatever anybody else thinks about me. [I still faceplant a lot, but less than I did. Tsuyoku naritai.] And it is in this place, psychologically, that I can rationally apply a Walk-Through-Fire rule - by noticing when it feels like a certain Something will be painful, and yet it is something-to-be-done. To these Fires, I strive to give my brain the rule "Oh, that's a fire? WALK THROUGH IT." Scheduling an oil change, and giving friends tough news, have been Fires.
At the beginning of Atlas Shrugged, Eddie Willers is returning to his job at the subtly decaying Taggart Transcontinental.
"No, thought Eddie Willers, there was nothing disturbing in the sight of the city. It looked as it had always looked. He walked on, reminding himself that he was late in returning to the office. He did not like the task which he had to perform on his return, but it had to be done. So he did not attempt to delay it, but made himself walk faster."
Should Eddie Willers have walked through that fire? I don't know. Whether Eddie Willers knew better, only he can say.