And in a lot of other cases, truth isn’t subjective. Are the three stooges better comedians than Charlie Chaplin? To me, the answer to that question is clearly “no”, but we can agree to disagree about that. Does Hillary Clinton run a ring of pedophiles? No she doesn’t, and that’s just an objective fact. There are blurry cases on both sides of that border. But just because border is blurry doesn’t mean that it doesn’t exist. All borders in real life are blurry if you look closely enough at them. That’s what judges are for, to make judgments about those borderline cases.

But to some degree these questions are irrelevant, because a lie is not just telling an untruth, It’s making a false statement which you know is false, or for which you have no sufficient evidence that it is true. you can’t be prosecuted for libel if you have reasonable grounds for believing your claim is true, even if it is false. But if you say Hillary runs a pedophile ring, and have no evidence whatsoever that this is true, I don’t have to prove that she doesn’t run a pedophile ring to conclude that you are lying.

This is especially true if you have some other motive for lying. In real life, no one would call a bag of rocks potatoes for no reason whatsoever, or do anything else for no reason whatsoever. If someone tells a lie, they expect to benefit from it, and if they benefit from that lie unfairly, that’s a crime. The fact that we only prosecute lies that do actual damage does not prove that the other lies are not crimes. it just shows that we have limited resources, and can’t punish all crimes.

You could say that lying is a tort, not a crime, and therefore should only be punished by lawsuits. That is pretty much what you’re saying in your last paragraph. Orthodox Libertarians say that all crimes should be punished this way. The problem with this is that it means only the rich get justice, because only they can afford to hire tort lawyers. Once you admit that certain lies are grounds for a tort case, you have already backed off from your claim that free speech has no limits. If you concede that there should be legal consequences for lying, we’re only arguing about details after that.