"Lexi Thompson appeared in May of last year with a towel provocatively draped around her neck," Randall Mell wrote.
Inkster noted that Ko, the Kiwi teenage prodigy and world number one, had never made the cover.
Spiranac can't make it as a pro golfer but has still been called "The Hottest Female Athlete On Earth" and is a social media star who posts provocative photos.
The 55-year-old Inkster, whose outstanding career includes seven major titles, wrote: "I know that stuff sells, and they are in the business of selling magazines, but I think people could learn more in an article about Lydia. It's kind of where our society is right now. I don't agree with it, but it's their magazine and they can do what they want."