They're just using you for their entertainment.

Also emphasize in your communications that they search was conducted under the false pretense that you had done something suspicious going through security in ATL when in fact you were connecting. They lie to people & then can't understand why they are distrusted & disliked?

I'd also suggest you send a letter to the ACLU. They pick their battles carefully and are unlikely to take up your particular case, but the more info they have, the better.

Were they wearing gloves? If not, you should insist that any person searching your belongings put on a clean pair. If yes, insist that they change them.