* Hour restrictions for passenger transport are significantly more stringent than for freight.
* Southern Air's fleet consists 737s and 777s -- not small planes.
* These plans have to fly over and into major metropolitan areas.
* Many parts of flying can be automated, but in the end, and for aircraft this size, you probably want a human operator in the plane for the sheer reason that they are better equipped to handle unplanned emergencies.
It's a tough call whether flying freight or regional airlines pays worse -- but in either case, you're anywhere from a quarter to half of what a software engineer of similar years experience in the bay area would make. The hours are in a lot of ways worse -- mostly because you're away from home a lot of the time, and you have really limited control of your schedule. (As someone who's worked as an on-call engineer for ten years, and who also flies, I'd take the on-call responsibilities over flying freight any day of the week.)
I'd agree that the article lacks for details. But, a relatively quick reading through things like airliners.net will give you an idea of the kind of hours and pay these guys typically work -- it's not an easy job. If we care about their safety -- and our own, given the number of freight aircraft flying over us every night -- we shouldn't write them off as just asking for money they don't deserve.