1. It is your right to not donate if you don't want to.
2. Blood VOLUME might be replenished in a day, but blood CELLS take time to grow, which is why he won't be able to sell plasma for three months after donating blood. This represents roughly $480 in lost revenue over that period, so IMHO blood collectors should pay people a minimum of $480 for the blood. Anything short of that would result in a significant financial loss. I am not in a financial position where I could reasonably take that $1,820 per year loss right now, and neither are most Americans. Thus, I will not be distributing my blood until they pay a reasonable amount for it, and I don't see why anyone else would. I would be happy to contribute blood if I were paid its fair market value.
3. If collectors actually paid for blood, I doubt there would be any shortages. Shortfalls are caused by the restriction of the free market in not allowing contributors to be paid for their blood. If capitalism were allowed to work without interference in this instance, the supply would be constant.
4. If a "doctor" is posting here, it seems rather unprofessional to say "This is just stupid. One of the most retarded things i've ever heard. " Would you talk to a patient like that? If you're going to bother replying, why not do a point by point refutation of his argument rather than just namecalling? Is it stupid because blood is individually wrapped and not stored in tanks? Is it stupid because whether a donor had insurance or not has no bearing on where the blood is distributed? If that namecalling had hurt his feelings, would it be construed as a violation of the hippocratic oath (or does that only apply while you're "on the clock"?) IMHO it is the responsibility of those with a higher education to provide a higher level of discourse then you might expect from, say, a sixth grader. It is especially the responsibility of M.D.'s and D.V.M.'s to attempt to educate people who may have misconceptions about health care issues. While I understand that it is typically impossible to teach anything to someone who knows everything, you didn't even try. If he's so wrong, why not link to a website debunking his misconceptions?
5. "Never argue with an idiot. First they drag you down to their level, then they beat you with experience."
6. OP, why not make a poll?
7. DeathBUA: My guess is that the way to deal with that patient is to check blood glucose levels and patient history for the possibility of diabetic ketoacidosis, prolonged starvation, or excessive dietary protein, then refer them to a nephrologist to treat their renal disease. This patient didn't just run a marathon, did they?