Sure they knew what the symbolism was. If you Google "autism awareness," you'll see that the rainbow infinity symbol is common, close to universal for autism awareness. So displaying a rainbow infinity symbol is not disingenuity, it's ordinary participation in an autism-awareness campaign. The librarians might have suspected that some of the residents of their town were so narrow minded, hateful, and homophobic that they would have a problem with rainbow colors of any kind, but who could suspect that town leaders would side with the haters and the ignorant? What the hateful, ignorant people in that town did is awful. What the leaders in the town did to endorse that ignorance and hate is equally awful. What the librarians did was loving, good and noble — and not the least bit disingenuous.