I never saw that stamp either.
Where have I been living, under a rock?
No, I am so racist and insensitive that all those ads when right over my head! Yeah that’s it!
The stamp came out in 1974, which is like yesterday. And you can buy them.
http://www.amazon.com/First-Retarded-Children-Helped-Postage/dp/B015DVHWSS
A comment on Reddit ...
I remember in the early 80’s a truck would come by and pick up donations from the houses in our neighborhood. My parents would always be like “Do we have anything to give to the retarded people? The retarded people are coming tomorrow.” I used to think they actually drove the truck around, and they’d bring it back to their retarded people headquarters and they all would dig through it.