The licensing board, and the protection of titles there under, is set up in such a way to protect the public (I won't go into how or why). This is similar to a doctor of medicine or lawyer. While these latter titles have a long history and are well established and protected, the title "engineer" is there quite yet not. The licensing boards are now putting steam into cleaning up the mess, but the self titled engineers are fighting back because they feel entitled to use that title too based on their experience (without license), common misuse, unregulated practice, etc.
Total BS, two fold. One, some engineering disciplines are just not well regulated yet which allows people to continue to work under that guise without limitations. These disciplines need to get with the program and adopt appropriate licensing requirements. And two, if you are practicing in an area that is governed by a licensing board, but you are not licensed, obtain your license (or appropriate credentials) or change your title. You are eroding the public's trust and confidence in the disciplines.
Mills appears to work in electrical design, is a member of IEEE, and has a business that touts being a "full spectrum product design and engineering consulting company". Yet without an electrical engineering license that is complete bull. It sounds more like he likes the title he used when he worked under licensed engineers and wants to stick with it because it has weight. Yes, it does, but for him it is misappropriated. I work in a engineering consulting firm, but we actually have engineers in nearly all of the common disciplines (sans nuclear and aerospace).
Appropriate alternatives: consultant, designer, technologist, scientist, builder, developer, fabricator, machinist,...