It is of course wrong. But when we hear of underwear bombs, people smashing planes into buildings and other people ready to cut innocent people's throat just because you are French or American, the perspective changes a bit. If the machine says you are suspected of carrying dangerous substances, you need to be checked, also in your private parts if necessary, according of course to written procedures and protocols insuring that things are lawfully done. It's a consequence of the world we live nowadays. As a fellow passenger furthermore, I wouldn't feel safe to go on a plane with somebody who set off an explosive detector and is not then carefully checked and questioned.