The next link in the donation delivery chain is unrelated? Agree to disagree.
Forgive me, but this is misguidedly reductive. No healthcare is provided in the US, by providers, without being subjected to capitalist exploitation. If I understand your thought process, a collective of the best pharmaceutical scientists in the world could create a completely non-profit pharmaceutical NGO, design and manufacture life-saving drugs, and give them away to hospitals (or sell them at-cost). But so long as hospitals then charge profit rates for those drugs, it would be ethically indefensible to financially support the NGO?
Is that not holding patients hostage in an impotent effort to force change in the broader healthcare industry? I donate to my local non-profit blood center, who (assuming they're similar to ARC) sells my blood to local hospitals at-cost, and then my blood is used to save a patient in need. The patient will then be responsible for paying the hospital exorbitant sums for my blood (from which the blood center doesn't benefit) and all the other services it provides, but what's the alternative?
Edit: would it make a difference if the blood center didn't charge hospitals for the blood, even though the hospital will still charge patients?