Did Aang's no kill rule advert the Red Lotus' members executions?
Not insinuating that they should or shouldn't have been executed, there's pros and cons to both sides. Since the White Lotus is seemingly influenced by Aang's principles, could it be that they were against executing the Red Lotus members because of his moral stance against murder?
For all I know, it may have not even crossed their minds, but I doubt that. For how dangerous the Red Lotus members were, I'm sure that this discussion would have come up. Tenzin and Katara and Sokka (if he wasn't dead by the time) could have been ones to argue against it. While Tarlok would have been less compelled, he'd likely trust them to decide on what is right.
I hope that this gets addressed some day in some media form.