They won't have mine either, though keep changing their minds as to why. I think they're okay about the hepatitis I had as a baby these days, and any exposure to malaria or secondary exposure to Teh Wrong Kind Of Gay™ I've had has long-since expired, but I'm now permanently tainted with 80s mad cow disease (CJD, that is, not Thatcher) from a transfusion.
Shame really, because it's a nice rare blood group.
I urge those whose blood they will accept to donate where possible, it really is important.