That scanner does not seem particularly disturbing, so long as the guard who is viewing the image is visible (although the image had better not be
) and the image is not stored. Since scanning someone for weapons isn't linked to your ID, I'm unsure of how this has privacy implications other than someone seeing a B&W X-ray image of you for a moment-- much less than someone might see in a public shower. Even if you were uncomfortable with it, you could still decline the scan and have the familiar pat-down if you like that better. I am not against security measures in general, and so far as it goes this one seems pretty tame (as opposed to searching your things, data on your computer, watch lists, etc).
However, I do agree that so much hysteria about terrorism is simply used to make laws that inevitably are used more against common citizens than the terrorists they were made for, and that is doing exactly what you describe: removing our rights in the guise of security when there is little to no more effective protection gained my such extraordinary measures.