No, seems to me that giantrobot's point is that adding randomness to port numbers is a light security through computational complexity (almost a shared secret), that can in turn be used to help prop up other security practices, such as fail2ban. Security through obscurity is reliance in security engineering on design or implementation secrecy

Preventing people from ddosing your auth logs leading to false negative fatigue that lowers the effectiveness of your login monitoring security measures is actual security, not security by obscurity.