Food and Drug Administration (FDA) regulations permit hemochromatosis patients to donate blood, provided the donor (the hemochromatosis subject) meets standard blood donor eligibility criteria.
The American Red Cross does not permit hemochromatosis patients to donate blood because it "has a long-standing policy that potential donors are not allowed to receive direct compensation for their donation (beyond the usual orange juice and cookie). Because people with hemochromatosis would otherwise have to pay for their therapeutic phlebotomies, they would in effect be getting something of value for being able to donate for free. Thus the Red Cross has ruled that such donations violate their policy" (read more here).
Bottom line: blood-collection organizations can determine their own protocols within U.S. Food and Drug Administration regulations, which stipulate acceptable iron levels in donated blood.
In a 2016 Editorial, West and Eder wrote:
Safety concerns historically stem from the possibility of creating an incentive to donate blood for free rather than to pay for therapeutic phlebotomy, possibly encouraging HH donors to deny risk factors for infectious diseases. In the Final Rule that became effective in May 2016, the US Food and Drug Administration codified the requirements for hereditary hemochromatosis (HH) donors in the Code of Federal Regulations (CFR), thus eliminating the need for a variance to collect whole blood more frequently than every 8 weeks (or double red blood cells more frequently than every 16 weeks) and distribute units without special labeling from HH donors who meet all eligibility requirements. Notably, the CFR retains the requirement for obtaining a prescription for therapeutic phlebotomy from a licensed health care provider and performing therapeutic phlebotomy free of charge... Since the molecular basis of the disease was elucidated in 1996, it has been posited that the condition itself poses no harm to the recipient. The question concerns the motives of the HH donor to give blood and the possibility of incentive to withhold information from blood establishments about infectious risk factors
In 2016, the American Red Cross wrote (despite its continued refusal to allow patients with HH to donate blood) a piece titled "Iron-rich blood is just fine, thank you!":
For decades, blood centers in the United States would not collect whole blood from donors/patients with hereditary hemochromatosis (HH), in some cases because it used to be that such units had to be labeled with the disease necessitating its removal... In 2016, the FDA encoded the regulations for therapeutic phlebotomy... Special labeling is not required, and units may be distributed if they meet regular requirements and criteria, as long as the therapeutic phlebotomy (TP) is ordered by a physician and the phlebotomy performed without charge.