This is a free speech issue. He is not claiming to practice engineering nor is he doing anything that would give that impression to the public. The board has used their very broad definition of practice on others who have seen fit to challenge a variety of Oregon’s laws and regulations. This is basically about this man’s criticism of red light cameras.
https://www.youtube.com/watch?v=Wi4brP0sXSQ
He would have a stronger case to make if he never identified himself as an engineer in his public statements or letters. One of my previous employers had their legal department did a thorough review of the laws and regulations in every state where we did business, and they came back and changed the way we even listed titles for our own staff in our marketing materials to avoid any problems like the one this guy is facing.