Why not everything is translatable?

There are some texts which you can not translate with loco. What is the reason for that? For example:

“Copy Text” if you right click a message
“Disable Sound Notification…” in the settings
“Select thread to display messages or” if no thread is selected.
“Open” if you right click thread
“More | Mute Thread” in thread option (right top corner)

Maybe there is more, but not sure.