Hi. I recognized your name. Love this essay: http://ranprieur.com/essays/dropout.html
Are you a technology worker? I've noticed many people with critiques of civilization are into technology.
For me it's definitely about the security of my belongings & personal safety. In certain places personal safety is less of a concern, but belongings are still so easy for someone to walk off with.
You can put those in a locker though
In the US, there are no more lockers in airports post-9/11.
This sounds like a rationalization. For me, the reasons not to sleep in public are that public spaces are designed to discourage it, and cops will wake me up.
Public sleeping should be a right, but if something like Sleepbox becomes common, it will become even harder to sleep without having money.