The Board's Final Report said, in a separate paragraph (14), that because "thinking and speech" (speech about his thinking, not "I'm an engineer")[1] were a violation of the law.
If you're arguing the board doesn't actually think that's a violation unless one also said one is an engineer, great, I've never disagreed with that; but they explicitly said "because [action definition X] you are in violation" and [definition X] pointedly does not include saying anything but "here's a creative application of math and stuff".
1. not the part where he said "I'm an engineer" -- the other paragraphs deal with that
If you're arguing the board doesn't actually think that's a violation unless one also said one is an engineer, great, I've never disagreed with that; but they explicitly said "because [action definition X] you are in violation" and [definition X] pointedly does not include saying anything but "here's a creative application of math and stuff".
1. not the part where he said "I'm an engineer" -- the other paragraphs deal with that