The Greek word used there is "PONEROS" meaning a man with malicious intent, it doesn't mean we should join in evil with them, like say when the Sodomites tried to get at the Angels via a lewd act, thus the Angels smote them. It's basically speaking about another man's actions are intentions towards you, in malice, mischief, or a calamitous way. It kind of means this, if a person spreads, lies ad rumors about you, do not stoop to his level. If a guy blocks up the creek so you can't get any water, don't go upstream and poison the water t get back at him. This is why Jesus references an eye for an eye, he's is not saying allow people to do Wicked evil things to you are your family per se, he's speaking about men/peoples character fault, I mean, yea, if a guy slanders you that is an evil deed, but it's not something you have to protect yourself from, God/Jesus isn't saying let people kill you and your family. As per the turn the other cheek, this is a simple argument/fight, he's saying, if someone gets angry with you and slaps you, look at them with love, and say, I still love you, that is far more powerful than retributing a punch to someone. He's not saying if 2 wicked people you don't know comes down the road, to let them come in and have at your family and take your possessions, that is a time for action, with a shotgun.