Here’s how typical people read typical job ads (typically), especially ones that are this long: Read the title. Scan for a dollar sign or the words “salary” or “salary range”. If both are good enough, scan for the first bulleted list of qualifications. Most ads call these “required qualifications”. If the reader meets enough of these, they scan for the second bulleted list of qualifications which is usually called “preferred qualifications”. Then, if they meet enough of both of these, they’ll go back and start reading in detail to understand the position better before they consider sending in an application or contacting the hiring entity for more information.
I suspect that most people expected your job ad to follow this form since it almost does. Your sections are labeled, effectively “needed” and “bonus”. It’s not until you get to reading the now-bolded details that you find out that not all of the “needed” stuff is required of the applicant and that essentially any one of the needed qualifications will be sufficient. Basically, you don’t have any required qualifications, but you do have a general description of the sort of person you’re interested in and a list of preferred qualifications. In this regard, the ad is defective as it fails to comport with the usual format of a typical ad.
Non-standard forms get experienced people’s hackles up. It often indicates that there’s something unprofessional about the organization.
Salaried professionals often cannot do an extra hour of work in order to donate the proceeds to charity. My employer basically prohibits me from moonlighting/consulting/etc. Even many hourly employees can’t get extra hours at work as that would be higher-rate overtime that their employer is unwilling to pay. Monetary charitable giving takes away from my current bottom line, but charitable working just eats into my leisure hours.
Since I cannot do extra paid work without fear of consequences at my primary job, my non-work time may be practically worthless. I can only use it to do things that I might otherwise pay someone else to do. If I can do work around the house, then I can save the cost of paying the plumber. Suppose I make $100/hr (nominally) and the plumber charges $50/hr. Assuming we can do the same job in the same time, I haven’t lost $50/hr by doing it myself instead of paying the plumber, I’ve simply lost the utility of those hours which I may not rate highly if I’d have otherwise laid on the couch watching Simpsons reruns.
Some units of caring cost more than others. I can donate $100 to charity, or I can do 100 hours of work for that charity using hours that only cost me $1/hr (presuming that I rate the utility of those hours otherwise spent low enough).
Clearly, people shouldn’t be derided for donating excess money (the “overemployed”?) to charity rather than their time, but I think the calculus is a little more complex than what you describe in your post. For those living near their means (neither under- or overemployed), there are additional economic factors that make donation of time heavily favored over donation of money. That a culture of valuing this has arisen to justify/rationalize such behavior shouldn’t be terribly surprising.