That's just stupid. I've learned to suppress my accent, not because I don't like it, but because the people that hear me talk with it assume I'm an uneducated dolt capable of drooling and scratching my butt. This attitude is especially stronger with the New England folks who speak with an unbearable accent, twisting pronunciations and skipping their "r"s.
No offense to New Englanders. I hate to say it, but most people who have held the opinion that southerners, especially with a thick accent, are generally stupid, aren't the sharpest tool in the shed themselves. Often times, they are intolerably dim.
This company is probably trying to avoid customers and the public from thinking of their employees in this way. That's what I would assume.
Just my opinion, of course....