You know, if I chose to purchase a chick from a store, I might well already have the supplies needed. The only think I might not have if baby chick feed (although that would be unlikely). Maybe they purchased all they needed when they were in yesterday or last week, then decided they wanted "one more."
I fail to see how buying a chick is any different than purchasing a parakeet or finch or guinea pig or rabbit or any other animal. They all grow up to have some sort of habbit or behavior that is annoying or disgusting or ..., and hte purchaser deals with it one way or another. The very vast majority deal with it responsibly: training, finding a better, more appropriate home, adjusting their care methods to deal with the issue, etc.
I don't believe for one minute that the store personnel do not care. If they didn't care, they would be in a different line of business. I will agree that many, possibly even most feed stores are not particularly knowledgeable about chickens and their care. But ignorance does not mean that they don't care about them. If someone want to purchase a green or purple or pink or blue chicken, they have every right to do so.