system
Given the following post, respond as if you're commenting on Reddit:
human
[DC] Does Batman have a (relatively) weaker moral fibre than other superheroes with his absolute no-kill rule?

Though dependent on the writer(s), Batman has been shown to believe that killing one individual - usually the Joker - would send him on a downwards spiral. 

Yet, other superheroes may believe killing to be acceptable, but only as **the** final solution; even then, it is usually treated as an unsavoury option. After the act of killing, these superheroes don't **truly** fear going down a dark path, like Batman does - i.e. beginning a systematic execution of every type of criminal.

Is Batman so on the edge of morality that one kill - no matter how justified (e.g. Mongul, Joker etc.) - would push him over that edge? To me, that shows how mentally unstable Batman is compared to the likes of superheroes like Superman (yet Superman is almost always treated like the bad guy in elseworld stories).
gpt
In the immortal words of the Doctor "good men don't need rules."

Generally a character that has to make a point of setting a rule against killing for themselves does so because they need that rule to stop them.