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

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

the display of bellybuttons

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

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

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

toilets being shown

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

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.

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

Remember the Hays Code?

lustful kissing is to be shown with care

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.