Who is the GP discussing free speech with? A random on the internet?
Oregon would not fine someone who was just discussing things among others, even peers.
But the Oregon State Board of Examiners for Engineering and Land Surveying, the one organization that wouldn't be deceived as to whether he was a licensed or unlicensed engineer, must be protected from his complaint?
So your point is that a "random" on the internet doesn't matter, but the Oregon State Board of Examiners for Engineering and Land Surveying should be able fine non-engineers for daring to bring engineering topics to their attention and claiming to the Board that they have an engineering education.
What he did do was an analysis which was sent to the owner of the specific problem.
Which he sent to the state licensing board, which he is absolutely privileged to do by the First Amendment.
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the government for a redress of grievances.
Mic drop. Licensed, practicing lawyer ouuuuuuuut...