Sometimes the government will screw up and mark someone dead even though they are not, they send that out to make sure the dead person is dead, not alive.
I think the "moron" could be excused. I work in an accounting office, and while that is not the same as a medical insurance firm, I think the sheer weight of the paper work might be the same. If said "moron" had in fact been typing notices all day, it's altogether possible that he/she was a little distracted when he/she was writing the note. It my have been to that person's family to notify them of the discontinuance, or perhaps it wasn't even meant to say "because of your death" at all. It was a goof, but let's give the poor fool the benefit of the doubt, shall we? Repetitive office work tends to dull the brain a little at times.
I work for California Department of Health Services. We are required to send that letter out just in case the person is not dead. It happens a lot since we get reports from many agencies such as social security, jails, other states, etc. The Veterans Administration thought my uncle was dead and it really messed up his medical coverage.
I also work for the California Department of Health Services and this happens all the time. Most of the time the people are dead however, and we do not recieve a reply back. :)