Final call, because yes, you don't understand this
""why can't the standard/default Mastodon installation/UI/UX ootb ... do it?", is that better?"
The standard "standard/default Mastodon installation/UI/UX" is a software distribution
It does *not* render itself
It must be rendered through some sort of user interface, whether that's a web browser (Firefox) a web browser add-on (Phanpy) or an independent app, most likely running on a phone
To make a poor example, it's like asking "why can't my single-overhead cam 2.0 liter gas engine take me anywhere"?
Because it has to be installed in an "app" -- in this case, a car