The main difference to your examples is that an “immutable OS” is in fact mutable, while none of your examples describe themselves with an adjective that is contradicting with their function/inner workings.
Flatpak is a pretty good name, because it makes software flat in the sense that it avoids having a (tall) dependency tree.
It’s not confusing at all… How is this any more confusing than:
Flatpak - they’re not literally flat…
Snap - I’ve never seen or heard any evidence of something snapping by any definition of the word I’m aware of.
Dolphin - what the fuck is this, no sea life whatsoever!
Kate - this is a text editor, not a person.
Distrobox - not in an actual box.
etc.
The main difference to your examples is that an “immutable OS” is in fact mutable, while none of your examples describe themselves with an adjective that is contradicting with their function/inner workings.
Flatpak is a pretty good name, because it makes software flat in the sense that it avoids having a (tall) dependency tree.