If you sit down and give the topic all due fair consideration, yes, there’s only one rational conclusion. However about of people just don’t want to think about dying, period, and will switch off on anything that makes them do so. I’m sure there are also misinformed people who think their organs can be freely stolen even if they’re not dead yet if they check that box.

I’m not justifying these people, mind you. I’m just describing how it happens. There is no good reason, but there are reasons.