Context, context. If you read the entire parable (and it IS a parable), you will know that this is not a matter of Jesus killing anyone or telling anyone to kill in this system of things.
Even when he was being arrested Peter tried to defend him by assaulting someone with a sword. Jesus said “Return your sword to its place, for all those who take up the sword will perish by the sword." Matthew 26:52
Luke in his account even said that Jesus healed the cut off ear of the one who was assaulted.
Back to context: Here is Luke 19:11-27
11 While they were listening to these things, he told another illustration, because he was near Jerusalem and they thought that the Kingdom of God was going to appear instantly. 12 So he said: “A man of noble birth traveled to a distant land to secure kingly power for himself and to return. 13 Calling ten of his slaves, he gave them ten miʹnas and told them, ‘Do business with these until I come.’ 14 But his citizens hated him and sent out a body of ambassadors after him to say, ‘We do not want this man to become king over us.’
15 “When he eventually got back after having secured the kingly power, he summoned the slaves to whom he had given the money, in order to ascertain what they had gained by their business activity. 16 So the first one came forward and said, ‘Lord, your miʹna gained ten miʹnas.’ 17 He said to him, ‘Well done, good slave! Because in a very small matter you have proved yourself faithful, hold authority over ten cities.’ 18 Now the second came, saying, ‘Your miʹna, Lord, made five miʹnas.’ 19 He said to this one as well, ‘You too be in charge of five cities.’ 20 But another one came, saying, ‘Lord, here is your miʹna that I kept hidden away in a cloth. 21 You see, I was in fear of you, because you are a harsh man; you take what you did not deposit, and you reap what you did not sow.’ 22 He said to him, ‘By your own words I judge you, wicked slave. You knew, did you, that I am a harsh man, taking what I did not deposit and reaping what I did not sow? 23 So why did you not put my money in a bank? Then on my coming, I would have collected it with interest.’
24 “With that he said to those standing by, ‘Take the miʹna from him and give it to the one who has the ten miʹnas.’ 25 But they said to him, ‘Lord, he has ten miʹnas!’— 26 ‘I say to you, to everyone who has, more will be given, but from the one who does not have, even what he has will be taken away. 27 Moreover, bring these enemies of mine here who did not want me to become king over them and execute them in front of me.’”
This is, very obviously, a parable illustrating that the Kingdom of God will not come immediately. He related the parable as they were approaching Jerusalem, and the apostles expected him to take the kingdom when he arrived there. But he was illustrating that he will go on a long journey and then return. It is at that return that he will "bring to ruin those ruining the earth." Revelation 11:18