1. A correspondent is considering painting his clothes or body with an expletive phrase directed at the TSA (visible under scanning) on the notion that it is protected political speech, even if offensive. I don’t know if it is protected speech or not. I personally would not use any profanity whatsoever or give in to any anger or outbursts.
2. Protest in a way that makes the point but doesn’t get you persecuted, arrested, manhandled, or thwarted from your travel. If an entrepreneur will manufacture a convenient protest symbol that you put on your clothes, such as a modest-sized but visible swastika with the words on it “SUPPORT THE TSA THUGS” (or GOONS), maybe that will do the trick. The possibilities are infinite. One could use a version of the TSA’s own symbols showing their eagle as an evil and invasive bird. All sorts of other messages are possible that allude to the TSA’s perverts, goons, gawkers, inspectors, and thugs.
3. Surround one’s private parts with lead or some material that the x-rays cannot penetrate and that hands cannot feel through. In other words, protect your private parts from scanning or groping. This gets back to privacy law.
4. Object on religious grounds. For that, you need to find some justification from your beliefs or bible or religious codes. See, for example, chapter 18 of Leviticus. In my opinion, it is basically profane when one is scanned or groped. That’s just my feeling. I’m no expert on this.