> The "donations" in this case aren't really donations. They're being paid in exchange for their blood plasma.
Which gets back to the question - what's wrong with that?
The alternative is not to pay people for donating plasma, and we can see quite clearly that that doesn't work - every country that does not pay for blood plasma donations runs a shortage, and most of them end up importing plasma from the US.
So, we have to pay for plasma, or else we won't have enough, which means people will literally die. Given that we have to pay for plasma, what's wrong with letting anyone who's medically eligible to donate do so?
Most of the common arguments against tissue donation (safety, incentive to lie, etc.) either don't apply to plasma donation or are no longer relevant thanks to the cost and accuracy of modern testing methods. There is no medical or financial reason not to permit the practice, and I'm struggling to see a moral one that doesn't eventually result in people dying because we refuse to collect the life-saving tissue that people are perfectly capable of providing and willing to provide.