Jason does a really interesting thing in UtRH where he consistently positions himself with the other victims of the Joker. Every speech he makes about the Joker is essentially "them and, worse, me". The worse there being because Jason is Bruce's son. His argument over the various moments (and this goes for Lost Days, as well), comes down to this: It is bad enough that Bruce didn't kill the Joker before Jason died. That, in itself, when the Joker had already killed who knows how many, when he had already shot Barbara (and Jason was alive when that happened, canonically) - that is nearly indefensible.
But even if he forgives that. Even if he accepts that.
The Joker then killed Bruce's son. And not only did Bruce not kill him them, he continued to not kill him, even when bodies continued to pile up. Note that at this point in continuity, not only does Joker likely have a body count well into the triple digits, he's also attempted mass infanticide and killed Gordon's wife (fiance?).
And yet. For his moral code, for his peace of mind, because it would be too easy - Bruce lets him live. And inherently, in the world of DC as it exists, letting the Joker live means letting the Joker kill. Even if you don't agree, it's certainly what Jason believes, look at what he says:
"I thought I'd be the last person you let him hurt."
So here's our scene: Jason, who has been positioning himself as both Bruce's son and also just another victim of the Joker, is holding the Joker at gunpoint. The options are: let Jason kill the Joker, or kill Jason.
Him or me, you have to choose.
This is a choice. This was always the choice. Inaction is still a choice. Every victim of the Joker is also a victim of the collateral of the no killing rule.
Him or me, you have to choose.
Bruce has to choose. No more pretending his choice doesn't have direct victims, no more acting like no-killing doesn't also mean accepting that the victim's of the Joker are a sacrifice to the rule.
You have to decide. You have to choose, now, while his victim looks you in the eyes. You have to choose while the victim still has a voice to tell you you're making the wrong choice.
But Bruce is Bruce. And he tries a third way. And everybody loses! Bruce finds a way to win and everybody loses - but then, maybe that's been the choice he's been making this whole time, over and over. Until there were graveyards full of the consequences.
If Jason is going to be wrong, let him be wrong and cathartic. Let him be wrong and still a voice of every victim. Let him be wrong and unforgiving, uncomprising, demanding every hero to choose, to look at the graveyards full of bodies and know their role in it.
Let him be rage and grief and blood crying for blood, of everyone who has ever been collateral.