Why do Americans and foreigners alike describe the USA as pr...

The ridiculous 2004 Superbowl ‘Nipplegate’ was a more recent reminder of how US attitudes have not really advanced much since the Hays code.

the display of bellybuttons

lustful kissing is to be shown with care

Remember the Hays Code?

any profanity to the Christian religion, e.g. hell, damn, God (unless used in a holy sense), or ridicule of the clergy.

For 34 years, movie and TV studios censored themselves to appease the Puritanical whims of Will Hays.

couples in the same bed, even if married. (Laurel and Hardy came before the code)

Some ridiculous highlights of the code in effect banned or discouraged:

disrespect of authority figures. Crooked judges are OK if they are also clearly portrayed as evil people

sexual perversion, including homosexuality (naturally), and sexual relationships between the white and black races.

Meanwhile, the rest of the world still sniggers at American prudishness.

toilets being shown

nudity, or even suggestions of it (e.g. a silhouette)

Why do Americans and foreigners alike describe the USA as prudish? Why do I see nothing prudish about the USA society? USA feels like one of the loosest countries although Americans claim to be very reserved.