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

the display of bellybuttons

Remember the Hays Code?

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

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

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

toilets being shown

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

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

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

lustful kissing is to be shown with care

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

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

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

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.