By switching the topic of discussion away from retirees and to ill people, you've effectively pulled a bait-and-switch.

Nope, I don't think so. You said:

They are not expecting some future change in their circumstances that would render death suddenly a thing that they want.

and this is plainly false -- it's false not just for ill people. Retirees are quite aware that their health and mental abilities will continue to worsen with age.