Re: AKA Libertarians
"hairdressers in most of the world don't have to be licensed"
And for professions where sometimes licensing is actually a useful idea, which can include engineers, those people can call themselves 'licensed engineers', or 'certified', to differentiate themselves from anyone who managed to pass an engineering degree.
This way you get the best of both worlds, licensing and certification where necessary, without making it pointlessly difficult for someone to use the word 'engineer' in their job title.