Korra beats the spirit of light to death:
Korra poisoning herself:
Korra removes her own bending:
Korra creating destructive spirit vines:
Korra letting the light spirit be sucked out of her by “herself”:
Korra letting the air be sucked out of her lungs:
Korra gives herself PTSD:
In conclusion: everything is Korra’s fault even when it isn’t, and Korra is secretly Unalaq, Amon, and Zaheer