Were you, then, truly using the technical definition? Do you actually feel you do not understand the mental processes and lines of thought by which people decide that immortality is undesirable? If so, it's worth discussing because it's generally bad form to give a strong dismissal a viewpoint that you know you don't fully understand.
I was using it in both senses. I've tried doing a lot of reading and talking about the subject, and it hasn't helped. The panel was an effort to further that as well. I really am trying to get it. I almost feel like I need Yvain to write a "Deathism in a giant planet-sized nutshell" post.
Can you explain what you find unsatisfying about the usual explanations of Deathism? Usual explanations being (listed from weakest to strongest reasons to support mortality)...
1) Belief in an immortal soul or afterlife
2) Misunderstanding of the premise (thinking that immortality would mean living forever but in gradually deteriorating mental and physical health)
2) Sour grapes
3) "Death gives life meaning", presumably by instilling a sense of appreciation and urgency
4) Concerns about the demographic and sociological implications of importality
5) Fe...
The video archive of the talk is available here
https://www.youtube.com/watch?v=Pm-5s__aZE0