Blarg, I did not care to read the article.
It's quite simple. You are using their service (yes I know you're paying). It is known to be a 'state of panic' where anything slightly suggestive of violence (even nudity) can cause you to not go on a plane. Simply wear a plain shirt, or maybe even wear it inside out. If you really want to keep your shirt on, drive.
I still think it's ridiculous for the reason that the USA airlines have been found inept at security; several people have videotaped illegal items being taken through with ease. If you are going to be awful at security, you might as well let them keep their shirt on.