If you were Gov. of AL when Mercedes, Hyundai, and Honda were looking to locate plants here, would you have told them that all their damn employees better damn well speak our language, or we don't want your plants in AL?
As much as I would tend to agree with you, your argument is fairly weak from an international business perspective. Do you really think that a company like this doesn't already employee English-speaking resources for these types of assignments? And, does Alabama even offer the written driver's exam in German, Japanese and Korean? (I mean, that would really be absurd in the first place.)
From another perspective, whether we want to accept it or not, American English is the international business language. Let's take Europe for instance... I had to travel to Spain, Czech Republic, Slovakia, Austria, The Netherlands and others to work for about six months. I had no problems getting around. The prefessionals in those countries have to learn English if they want to stay competitive, and they even make it known that it's "American" English that they can speak. Just recently, I helped negotiate a project with the APAC region for an international financial organization. Everyone from the client spoke perfect American English, and their office is located in Tokyo.
I don't see the candidate's message as an issue even worth the costs of this advertising, and the arguments that I've heard against it are just as weak and simpleton. To think that an international organization would be influenced by this short-sided reasoning is just as absurd as the original ad.