> I am a biologist and my medical friends and I agree that both volunteered and paid blood donation in the US is mostly safe

For the non-biologists, can you elaborate on this? My understanding was that paid "donations" aren't generally considered to be as safe. For example, the GOA report (referenced at [1]) seems to say that California's plasma supply (which is not required to report whether the donors are financially compensated) had an HIV rate of around 5 times that of the red blood supply.

[1]: https://www.statnews.com/2016/01/22/paid-plasma-not-blood/

I agree that the deferments are often illogical, but from what I've read, I think non-payment makes sense. Blood banks are technically allowed to pay for whole blood, too, yet apparently no hospital would accept it, which leads me to believe it's not just a PR issue.