Usury is Exploitation?! Give me a break Socialists!

I often laugh in the faces of socialists. Not because I hope to insult or demean them, but simply because the stuff that comes out of their mouths is so ridiculous. Recently I have been following a very interesting anarchist blog and while I agree with the main premise of this lefty-anarchist philosophy (rejection of arbitrary authority), I still can't help laughing at the absurdities I sometimes find written there. One such thing the collectivists have always ranted about is the charging of interest - the mythical SIN OF USURY. From what I understand lefties oppose interest because of their silly belief in the (I apologize for the swear-words coming up) LABOR THEORY OF VALUE. They say that it is immoral for one man to loan a thing to another and demand payment for it because while one labors over the property, the other simply gains without performing any function. I have two critiques of this silly argument, a moral one and a practical one.
Let's start with the practical one because it immediately shows the absurdity of any anti-interest theory. Let us assume we live in a world where interest may never be charged. In other words, no one may charge anyone else for lending them something. First off all current rent agreements would become not only null-and-void, but subject to some kind of penalty. For example my parents, who rent their house from a landlord, would be left homeless. The landlord, meanwhile, would have an empty house for which he has no need... I would also be considered an immoral person for using a credit card on which interest is charged monthly if I do not make a prompt payment. I really don't understand how people would cooperate in such a society. Personally I would not lend things to strangers unless they paid me and I do not expect anyone to act differently. So why should anything ever be lent out? On a small scale maybe this could be solved by creating some kind of communist tribe-unit, but lack of usury is utterly incompatible with any economy of scale. Furthermore, it is important to point out that most influential historical figures who promoted the usury-free society did so on religious grounds (Martin Luther or Adam Smith, for example).
Now the moral critique. What right does anybody have to tell me what agreements I can or cannot have with someone if they have no effect on a third party?! Again, this is socialist meddling - moral crusaders do this all the time, whether Statist or Anarchist. If I voluntarily agree with my bank that the rules of using my credit card are such as they are, nobody has the right to impose their will upon me or the bank. Doing so would be tyrannical and simply evil because it constitutes aggression. How many times do I have to tell you people - LIVE IN YOUR LITTLE COMMUNE, KIBBUTZ, OR WHATEVER, BUT KEEP YOUR MITTS OUT OF MY PERSONAL LIFE. I simply do not care about you people, so why do you have to care about me? Any interference in a transaction between consenting parties cannot be morally justified in any way. This is why we libertarians oppose anti-drug laws, for example. Nobody has the right to enforce them, it's as simple as that. Why do we not ban boxers from fighting in a ring? Because they do harm to one another VOLUNTARILY.

And I promise you all an absolutely smashing critique of the ('scuse me again for the bad language) labor theory of value coming soon.

I am very impersonal in my criticism of socialists because I simply do not care what such people do with their lives as long as they do not impose anything on me. This is why socialist-anarchist are a strange people... What do they want? Do they want to attack me to prevent me from setting up perfectly voluntary arrangements with others? I do not care about them - I care only about what they may do to me. As George Reisman put it "the Idiots of socialism are slaves, but they are no one's property and therefore no one's loss". At least he capitalized Idiots. Amen to that.