Unless someone sees the exact numbers, or has a comparable web site, they have no idea what they really are. The author is building one assumption on top of the other, meaning each step off makes the end result even further from reality. I haven't touched Amazon's affiliate program in years, but from what I remember the % of sale was category based, and many items would pay out in the low single digits.
Web site owners soliciting donations while making money from affiliate links, not unusual. Owners making money from affiliate links while not disclosing them, even more common. Journalists attacking bias while making money and not disclosing it, unusual and certainly worth investigating.