I think you just have to come up with strategies to force people to express these clichés in different words. With this one in particular I'd try to work down a tangent about how Libertarians take this as their basic "anti-violence" tenet in
the NAP. Then I'd try to locate the boundaries where people end and begin through Buddhist/Hindu arguments (that usually ultimately deny those boundaries.) Penultimately, I'd start joking about all the strange things that Libertarians are forced to refer to as violence to justify their responses.
Then I'd circle around to the original subject under discussion, and argue that the boundary that they drew may not be extreme enough in light of some of the things we had just discussed, and ask how they justify drawing the boundary in that particular place.
Now we're having the conversation that I wanted to have in the first place, and I've positioned myself to argue from a perspective farther from the position that I actually hold than the person that I'm arguing with is. Their disagreement with the arguments that I am now making will generally push them closer to my actual position, and their agreement with the arguments that I'm making will push them into defending an obviously extreme, outlying position (which is what I chose it to be.) Both create cognitive dissonance that can be resolved by accepting my actual position.
edit: There are infinitely many other angles, too. I like talking about desert, as in "the property of deserving", because it's not something most people have thought about as such, and it can be spoken about in pretty ordinary language. Then you're talking about positive liberty rather than the negative liberty of "freedom from restraint." To continue to use the cliché in those terms involves having to change signs (-/+), which is difficult and requires thought (if you never learned DeMorgan's rule or practiced explaining it in plain English.) Now you're having a real conversation.
tl;dr: If you can force people to reword their clichés, you can have a real conversation. The best way to do this is to attack them from strange angles.