Contrary to what I was expecting - that GET is the only one whose method parameters are provided on the request URI - DELETE behaves the same way as GET.
I was about to ask why DELETE /users/{userId} with a message body of {action: ‘delete’} was performing a disassociate, when I saw that the default action is disassociate and noticed that my request format was different than the documentation’s request format.
Hope that helps someone else!