While on this issue I mostly agree with the defendant, I think it's reasonable to protect certain titles (engineer, doctor, lawyer, dentist). For a parallel situation, imagine a hypothetical person named Phil, who has a doctorate in psychology. They call themselves "doctor" and give medical advise to the unwitting public, despite having no relevant training.
In this case, the guy had training as an electric engineer, but was commenting outside of his proven realm of expertise. However, he wasn't deceiving the public by representing himself as an engineer-for-hire, though, which I think makes it forgivable. I just found the free speech ruling to be over-broad.