Disclaimer - I'm not a Bible scholar. However...
In Luke 6, where the turn the other cheek, etc., is discussed, Jesus is giving instructions and a pep-talk to the
disciples. It's not a speech to the multitudes (though a crowd is in attendance).
e.g.
20. Looking at his disciples, he said: "Blessed are you who are poor, for yours is the kingdom of God.Although his words can be taken as universal, and I think most people take them that way, the passage in Luke can be read as explicit instructions to those who will work with and follow him. Theirs is a hard lot because they have to be purer than most to spread the news the way Jesus wants it spread.
Remember that Jesus whipped the moneychangers in the temple, as discussed earlier. Exclusive turning of the other cheek wouldn't have permitted that, would it? And consider Luke 10 (similar to Luke 9, but with a bit more emphasis), where he's giving instructions on what his disciples should do on travelling to a new town:
10 But when you enter a town and are not welcomed, go into its streets and say,
11 `Even the dust of your town that sticks to our feet we wipe off against you. Yet be sure of this: The kingdom of God is near.'
12 I tell you, it will be more bearable on that day for Sodom than for that town.
Doesn't seem very peaceful, does it? The town must actively welcome strangers or be destroyed?
It's very difficult to find passages in the Bible without passages which contradict them under (sometimes) different circumstances.
Best of luck with your search.
Cheers,
Scott.