The rule itself is vague, it clarifies that you may not KILL someone after robbing them unless they bring it upon themselves which is completely different from robbing/looting after killing.
they are two complete different things.
"Killing or inflicting heavy injuries
before, during or after a robbery/scam (or attempted robbery/scam) is disallowed, unless the victim brings it upon themselves."
It is not vague, it is clearly stated in the rule. It doesn't matter if you intended to rob them or not, the act of looting a dead body is considered a robbery.
Edit: As Witting said, if you are not affiliated with the murder or murderers, then this rule doesn't strictly apply to you but you must be able to answer for your actions.