Some apps (which have a built-in Tor daemon) will not work on TAILS or Whonix (ie systems that force all their traffic though the Tor network) because this creates a Tor-over-Tor connection. Why?
Examples of such apps:
I understand that OnionShare works by creating an Onion Service, which is more complicated than apps that just connect as a client to Tor (eg Tor Browser).
And I also understand that running Tor-over-Tor is not advised. Sure, it will have performance (and privacy?) degradation. I understand that. But I'd expect that these apps would just run slightly slower. The reality is they completely break. Why?
Please explain [a] "like I'm 5" and also explain [b] "like I'm a Tor developer" why some apps with built-in Tor daemons fail to run on a system that forces all its traffic through Tor.