It isn't "hateful", it is reducing the likelihood of someone getting an infectious disease from a blood transfusion, by any means necessary. Even if you wave a wand and improve testing, then remove the ban, you're still going to have higher rates of infection than if you improve testing and keep the ban.

If public health is improved more by the ban, than it is reduced by decreasing the supply of blood somewhat or increasing the cost of testing, then it is totally irrational to insist the ban be removed (assuming your goal is to maximize public health).