I would like to know this as well. Why is OpenVPN risky?
In seriousness though, the author is not a infosec expert so I would take the advice with a grain of salt.
Seems he was correct: https://ostif.org/the-openvpn-2-4-0-audit-by-ostif-and-quark...
Also, he's a business school grad. But you taking infosec advice from one is none of my business.
dont forget to downvote this one too on your way out.