

Sure, there is that difference. But the series doesn’t even address the fact that he’s already killed hundreds of people. Intentionally or not, it’s still absurd to hand wring about killing when you’ve already killed hundreds of people, accidentally or not, and the one person you’re worrying about taking down is literal genocidal maniac. To me that just sounds like not being willing to take responsibility for your own actions. Intentionally or not, Aang killed hundreds of people. And it’s not like he never went into the Avatar state again after taking out the Northern fleet. Hell, he fought Ozai while in the Avatar state. Maybe he should have just “accidentally” killed Ozai while in the Avatar state and just washed his hands of moral culpability, just like he did all the other people he killed before then.
Regardless, Aang found a way to make peace with the fact that he had taken hundreds of lives. But when the person in question is someone of power and renown? Then it becomes something to fret over.
What really gets me is that not even ordinary autoclaving can destroy the CJD prions. Those things are fucking terrifying. Look at sterilization recommendations for surgical instruments that have been exposed to them. The first recommendation is “destroy them.” The second is, “if you simply must reuse them, boil them in lye in an autoclave for an hour.” And even then we’re not really sure if this is effective at sterilizing contaminated instruments; the recommendations are based more on lab studies, studies in Petri dishes basically. They’re largely not based on actual studies on contaminated surgical implements.