I find it hard to believe that kids brought up in Texas would react this way. I'm guessing it's a bunch of immigrants totally disconnected with the political process and what it means to live in the U.S.
I'm not sure where exactly this occured. If it's in a more urban area, the open presence of firearms may not be anywhere near as common as it is in more suburban/rural areas. The presence of firearms is still probably high in those areas but I would be surprised to find that they are as openly discussed and displayed as they would likely be in more rural areas.
I would like to believe that Americans in general, and our more Conservative citizens (including Texans) would be capable of understanding how not to make themselves look like, or act like FOOLS. Considering that this is at least the second of these "open carry" issues in Texas recently, I'm beginning to reconsider that idea. Common Sense and Common Courtesy should dictate that there are appropriate and inappropriate times and places to carry a gun, and appropriate types of firearms to carry for self-defense in a public place; Openly or Concealed. These individuals, and their predecessors have crossed that line, so far as I'm concerned.