acerbone,
Welcome aboard, and even if some, like me, disagree, please know that we welcome differing views and debates.
All that said, I don't understand your issue with that post of Rob's. He is saying that you should not carry open in order to make a political statement. He is not saying it is politically incorrect to open carry. Rob does believe that concealed is the best for retention, the element of surprise, to not draw undue attention of both the general public and law enforcement that should not be distracted by you, and to not single you out as the first target in a violent situation.
In this post Rob is not saying that open carry is politically incorrect or harmful to our stance and 2nd Amendment protection of the Right.
Keep in mind that the more well known and the broader the education area of an instructor the more careful they are going to become with their words. This is because they always have to be aware of the most stupid person that will quote them in public, the media or a court of law. They need to be very careful with what they post on a place like facebook, put in their videos or do and say on broadcast statements, because there are idiots out there that will take it without thinking and act. In a private class they can say and recommend more, because they know their students and can make sure their words are fully understood.