Equally, killing is not absolutely immoral either - it has context, such as in defense of one's life from an aggressor.
How is this relevant? No one in this thread is contending that killing is absolutely immoral. There are those contending that lying is absolutely immoral. I think it's already been demonstrated that this is not the case. So then the question becomes when is lying immoral and when is it not? And under what circumstances? And how can we apply this to a concise ethic which is not in contradiction of other ethical principles and valid theories of morality?
The commonality of context of both of these (lying and killing) is the violence or lack of it.
Thus, killing and lying are absolutely immoral absent of violence.
I see what you're getting at here, but the difference is killing necessarily requires violence--either of the aggressive or defensive persuasion. Lying, on the other hand, does not necessarily require violence of either persuasion; so it isn't as analogous to killing and thus can't really be held to the same reason.
Because lying distorts the truth - and free men base their decisions and actions on truth - thus, by destroying truth, you lead men to make bad decisions, which harms them.
Lots of things can distort truth, this doesn't make something immoral though. Moreover lying does not destroy truth; truth continues to exist regardless of what lies may be told. Further still, lying does not necessarily compel anyone to make any decision or choice, nor does it necessarily force anyone to make any decision or choice. So these assertions that you've made above are not necessarily true, which makes the conclusion which you've extracted from these premises flawed.
If my girlfriend asks me if I like her new hairdo, and I tell her it looks good, even if I have further or contrary thoughts to what I said--is this immoral because it isn't precisely true? The truth in this case is my subjective opinion of her new hairdo--I have not lied to her out of malicious intent; my lie does not harm her or her property in any way; she likely even feels better because of my lie. Did she ask me this question with a preference for the truth, or was she asking me this question with a preference for positive reinforcement regardless of the radical truth? Is she entitled to the thoughts which only exist in my head which can be properly described as my property until such a time as I choose to freely share them? Is radical honesty the only moral course?
All we can accurately say from the above scenario is that I am responsible for the effects of my answer, however much of a lie it may or may not be. I don't see how the above is immoral, whereas in another scenario, if a blind man were to ask me if it were safe to cross the street, and I tell him "sure" even though there is oncoming traffic, and this results in the man either causing a traffic accident or being harmed by oncoming traffic; my lie is essentially what has caused this, and thus I am responsible for this. We can argue that this is immoral, but this lie is much different than the previous lie due to the effects of it.
This is why I think, outside of instances of fraud which are necessarily immoral, we cannot say that lies (even in the absence of violence) are necessarily immoral without considering the effects of the lie in question.