Converting this guy to hamburger means no one can take hostages to try for an exchange and the hamburger isn't going to be issuing any coded messages to his followers. His human rights can no longer be violated - no worries about religious or dietary accommodations. And the use of a non-explosive device limiting the chance of anyone claiming to be completely innocent and having no idea what he did for a living also dying was apparently successful.
If his followers believe there is an afterlife, they should be happy he got there, maybe not in one piece, but still .There's no details on the conversion process to post-mort existence so just assume he's surrounded by other similar spirits.
Think of the engineers of that system - the aerodynamicists and the controls engineers and the EEs - all creating a collision, likely managed from half the planet away, launched from tens of miles away, onto a target the size of an a-hole. When I compare this to the alternative of sending 500,000 troops to go door to door asking if that guy was home? This was a far better choice.