The notion that one must shrink from aggressors and submit to their tender mercies is what I would consider less civilized.
Two different things. The duty to retreat "to the wall" was incorporated in the common law numerous centuries ago to provide a means of establishing whether one who had committed homicide had done so in consensual combat, had committed murder, or had been forced to kill for the legitimate purpose of self-preservation. How else would people know? Sounds very
civilized to me.
Didn't apply in the home.
Submission is something else entirely.
Today some states have "stand your ground" laws. These obviate the need for proving, in a defense of justifiability, that safe retreat was not a viable option.
Just thinking aloud, they may--conceivably--have the unintended effect of making it more difficult to establish that the use of deadly force was immediately necessary as a last resort if retreat has not been attempted, however.