Question about Ninja looting...

[Dirtnap]

So I read the first few pages of that chanter ninja looting thread and it leaves me wondering.

Why are corpses not just lootable by the group who killed the mob? Why even bother having the timer that makes it lootable by some random passerby?

Why is it bannable/suspendable to loot a corpse that is now considered lootable by anyone?

I understand that it is a huge dick move to roll up on a corpse you didn't kill and loot it. Its your fault for not looting what you wanted off of it after you killed it.