Actual athletes are training for a specific goal. If you're a swimmer/runner/pole vaulter/whatever you may want a different program to focus on things that improve your performance in that discipline.
Most people who go to the gym just want to be in shape, and for that goal the author is right - assuming "getting in shape" to you means developing a fit and capable body. He's also right that a lot of people misguidedly waste a lot of time on unnecessarily complex routines that don't even work that well, and spend way too much money and effort on supplements.
Attackers aren't hampered by organizational imperatives. They are free to find targets of opportunity and move between them as it suits them.
Defenders usually have to justify their work to management and balance "real" defense work with things that reduce liability. This ends up being a prioritized list.
I blame JIRA for giving the attackers an advantage.
https://www.youtube.com/watch?v=3395_T1N-fo