I'm a bit confused about why you don't perceive the above scenario as a software bug that needs to be fixed, specifically a programmer error dealing with compartmentalization.
Compounded further by another error when entering safe mode, as safe mode by design doesn't load any non-essential programs on start. Neither would Linux single-user mode without X. You should always be able to enter safe mode if a particular non-system program is messing things up. That's the point. Anything else is a bug and deviates from spec. If a programmer tried to argue with me that the spec was wrong in this case, they would be fired on the spot.
Firefox also doesn't auto restore tabs if it was shutdown improperly, so what you describe shouldn't happen. Has it ever happened to you? Or are you just arguing against a strawman?