GPON Vulnerable and Insecure?

I read this on https://pierrekim.github.io/blog/2016-11-01-gpon-ftth-networks-insecurity.html and it says "The security mechanisms already defined are based on the assumption that all the GPON elements will be strongly physically protected. GPON communication are vulnerable to severe security issues, such as:Fake/Forged OLT: currently no OLT identification and authentication mechanisms have been specified, Man In The Middle (MITM) attacks, and Several kinds of DOS (Denial of Service) at GPON level e.g. during the activation phases.". So with this in mind do business and government try to avoid using GPON? :p