(just a complete guess) to feel like they have power over others. they know the decedent did not authorize their skull to be (say) mounted on a cane next to th

(just a complete guess) to feel like they have power over others. they know the decedent did not authorize their skull to be (say) mounted on a cane next to their throne, or their teeth to be made into (say) a necklace. I can see how there could be a market for products that say "look how badass I am, that I have human remains over my doorway", just like some people do with their (egregiously) lifted trucks, or other status symbols.