Agree. Stop using postmortem for neutral retrospectives.
Postmortem ("after death") is a term used for diagnosing what went wrong, when something went wrong.
It's the right term to use to report on a service outage on a website, for example.
From Wikipedia project post mortem: "is a process, usually performed at the conclusion of a project, to determine and analyze elements of the project that were successful or unsuccessful. "
Why use "after death"? it's not like latin words don't have meaning...