It seems to challenge the idea of the justice system, but in a very subtle way. Are there other flaws with this reasoning? Is the confusion between the idea of a greater power's justice (law of nature, god, etc) and human justice perhaps?
Justification always is an appeal to some higher power. There will be a great deal of disagreement as to what those higher powers are in the case you allude to, so I will intentionally not get into them. But the general pattern does fit into the topic of philosophy.
Most systems I know of which assign you responsibility for your actions have some concept of proximal cause, in one way or another, which is the last act of volition of any agent which lead to an outcome, such as one's demise. If another actor acted last, making their response the proximal one, the question becomes whether it was reasonable for you to assume this was an outcome to consider.
A major challenge with thinking like these is that often there are multiple causes, not all of which are proximal. Personally, I drive to work every day. There's a chance I might die because someone plows a 1 ton block of steel and aluminum into me. I accept some responsibility for my choice to get into the driver's seat, but I choose to assign more responsibility to a drunk driver who crashes into me.