Seth Godin's Halloween blog post focuses on marketing, but one question that he asks is:
"How did fruit end up as treat non grata?"
A part of the answer to that is the attitude that has developed that sugar greed is a part of the Halloween fun, thus anyone who doesn't cater to it is a party-pooper who hates children.
But another aspect is fear. Remember all the urban legends about razor blades in apples? The take-home message was that homemade treats could kill you. The only treats to be trusted were the ones that came in sealed wrappers with corporate logos on them.
A home-made cookie or piece of fruit is treated by many as "candy from strangers", and therefore dangerous. Unfortunately, we are often so unfamiliar with our own neighbors that we view them as strangers who could potentially be homicidal maniacs. Better off with something from the Hershey's company; we know we can trust them.