I guess they want that little extra money that the untradeables give when dropped on death.
It takes a person with a lot of mental stress to do stuff like that. People in their rage do stupid things. Like for instance people breaking tentacle whips and taking the kraken tentacle. It's really sad that there are people in this world that go out of their way to make life hell for the people around them.. Can never explain, but main reason, I would say, is cause they're angry and need to take it out on someone.
At the end of the day they are only gonna hurt themselves more and more.