Some exclusions make sense, but unfortunately a great many of them arel behavior-based. This is because there are blood-borne diseases, like some of the hepatitis viruses, which a donor can spread to the people who need his blood, long before he has any signs or symptoms of the disease. That means, long before his lab tests are positive. So they exclude anyone who might have hepatitis based on risky behavior.
But this excludes thousands of willing donors who aren’t infectious, because of the description of “risky”. Monogamous gay men in committed partnerships. People with recent tattoos. (Used to be anyone with a tattoo - ever - they had to redefine “risky” for that.) One that really irks me, because it’s not an exclusion in Europe but it is here, is people with hemochromatosis.
Hereditary hemochromatosis is a disease in which your body sucks iron out of your diet as if you had a beach-sweeping metal detector in your stomach. People with this disease overload themselves on iron, and may die of it in their forties (for men; women are relatively protected because they bleed a little every month). Until they develop arthritis, cirrhosis, heart disease, etc. from iron overload, they are perfectly healthy. The only good way to get the iron out of their bodies is to take blood out of them.
In Europe their blood is taken from them for free and is used in blood banks. In America their insurance has to pay for the blood removal, and the blood is either discarded, or used in research. Why? The FDA is afraid of “motivated donors”.
Stupid, says I. Stupid.
An interesting note on HH - it can be traced back to one small tribe in Ireland about 20,000 years ago. It was an accidental mutation, but it seems to have spread widely through the Celts (who, at the time, had a range from Ireland to Moscow, Denmark to Italy). It is likely to have spread widely because diets at the time were so iron-poor. Specifically, everybody was starving, there was next to no meat to be had, and if you could hoover iron out of the poor vegetables you could get, you were likelier to survive and leave offspring. People with an irish or German heritage have one chance in four of carrying the allele.
If you are German/Irish I suggest you get tested for HH. It’s a cheek swab test and, in the US, it costs about $125. I am not associated with any lab that does testing. I just autopsy people who have died too young.