So that entry in the Color Management window is for the "input" (camera or scanner ICC profile)? Interesting.
That certainly does not leap out at me.
Input is input, it could be a camera profile, camera Exif ID and associated jpeg profile, scanner profile, sRGB or Adobe RGB etc.
It makes it clear above that section that lines are inserted for cases when no embedded profile is found. Any decent editing software will do this anyway, so no problem.
Qimage does not "assign" a working space like an editing program, it reads what the colour space of an image is, or you tell it what to use when there is no data.
Q follows the normal colour management process for viewing & printing; Input > Convert for monitor or with monitor profile, or, Input > convert with Printer profile.
The layout of the CM dialogue reflects that.
I realise I've been using Q for a long time and these things are second nature to me but I hope you'll soon into the Q way of thinking
Perhaps Fred will add to this and put a different angle on it to help you.
Terry