"It would probably not be a smart employer who allowed their employees to be seen to publicly bad mouth not only their product - but their customers. "

Not necessarily so. First of all, your label of "bad mouth" is simply your opinion. The quote that you have cut and paste numerous times is simply an opinion from Joe. Most "employers" would not disagree that an honest evaluation of pros and cons will actually help the image of the company and go far to improving. Companies need to be open and honest.

As for bad mouthing a customer, it is easy to say that it is a no-no. However in reality there are often circumstances where it is necessary and will actually build respect. A customer who tries to get away with behavior that disrupts my business needs to be dealt with. Hopefully things won't get out of hand, but sometimes they do.