I’ve been thinking about Matthew 5:39 much recently as well. This is kind of the direction I was hoping this other thread might go.
I don’t have an answer for you, but I have long had similar questions. In my mind, the command to not resist an evil person would be simple enough for me to obey if my own life were the only one I were responsible for. Then I would be free to be a personal pacifist and take my licks unto the grave. But as a husband, a father, a son, a neighbor, etc., it seems that obedience to Christ demands that I be willing to resist an evil person in many contexts.
Learn to do good;
seek justice,
correct oppression;
bring justice to the fatherless,
plead the widow’s cause. - Isaiah 1:17
Open your mouth, judge righteously, defend the rights of the poor and needy. - Proverbs 31:9
But if anyone does not provide for his relatives (i.e. to tend to their bodily needs, which doesn’t exclude physical safety), and especially for members of his household, he has denied the faith and is worse than an unbeliever. - 1 Timothy 5:8
How do we marry all these types of things together with Matthew 5:39, coherently? I’m not sure, so I’m just going to be over here cleaning my .45 and let wiser men respond.