Does the author even consider that perhaps senior discounts are not at attempt at charity but, rather, an attempt to secure the business of a demographic that otherwise would stay home?
You have perfectly described the heart of the matter. In the realm of managerial economics, the term is "price discrimination", where a firm maximizes its revenues by charging a lower price to the demographic which otherwise would not purchase. It's obvious the writer of the piece has a meager education in economics.