First of all - thank you for being a blood donor. It makes a big difference. I too have given quite a bit of blood over the years, and yes - it gets frustrating when the paperwork and the “stuff” just gets deeper and longer.
But I would like to throw out a POSSIBLE scenario based on my own experience -
A couple of times in my donation history, there have been “issues” - both times were the result of bad sticks. The first one was while I was in college a couple of decades back, the second about 6 years ago...
The first time, they collected about a half of the “pint” they normally take. The second time there was a bad stick - they got a bit less than that. What I was told then (American Red Cross) was that they cannot, by regulations, use partial donations directly for transfusions and similar whole-blood uses. Instead, it goes to research or to the manufacture of medications. That way it doesn’t get “wasted” (which is the case if they couldn’t use it for that).
There is a possibility that the organization you donate to has done the same for years - but found it necessary for whatever reason to give legal notice (people are lawsuit happy and conspiracy happy these days).
And no - I am not trying to put you in the above categories - but just throwing out a possible scenario. I cannot speak for the bunch you donate too.
As for thanks, you're quite welcome but to me, its really just something that I consider to be 'the least I can do', since I'm healthy, and there is no alternative in some cases for folks than having real human blood.