Public decency and public bathrooms

We all know that the US is very weird when it comes to what they consider to be decency. If you say fuck, you're frowned upon. Making out in public is a no go. And don't you dare show a nipple on Facebook or in a movie.

But why then do they design their public bathrooms like peep shows? I remember having bowel problems in 2010 and barely making it into a bathroom in Washington DC close to the Lincoln memorial. While I sat down to mind my own business, I could see through a gap roughly 2 cm wide (that's about one inch) at a boy of about 8 years... watching me.

Today I went into a Bojangles and the cabins had doors so low that I could easily look over them. Why do they even bother to put up toilet cabins if they want to enable everyone watching you taking a shit? Why not put all the shitters next to each other like urinals?

Is it a fanatic fear of someone having sex on the toilet (let alone gay sex)? Or of someone shooting heroin there?

What's the reason? Why do they design bathrooms like "watch someone take a shit" peep shows?