You pay your taxes don't you? Where that dollar goes after it leaves your hand is intirely in the governments hands. Same goes for the blood bank. You gave hoping that the blood is not used as a direct transfusion. If witnesses can consciencously accept fractions then that is what you were giving to.
Don't give in to those pea-brained so-called elders. They haven't a clue what is important.
Give Blood and stay healthy.