That is something born out of the current system, only possible because the existence of banks and compound interest. If the banks weren't already in the position to lend money (and factor out derivatives) you wouldn't be able to get into this position.
The charging of interest is a self perpetuating mechanism which works both ways. If nobody charges interest and only relies on trust and/or compassion it is no longer needed.
But anyway: I recon, that lending for interest might not be feasible to prohibit but rather only provide the legal right to get back the loan without interest. On the other hand the lender might come up with other, yet prohibited ways to collect interest which is why it might be wise to prohibit it in the first place.
PS: All these considerations are theoretical in nature, since I have no idea how it would be like living in a system without usury. It is only the way I personally think thing
should work and it might not be feasible in current society. I attribute myself to parts of syndicalist and primitivist schools of anarchism with a spice of futurism, so it might be understandable that my views might seem a little ''far fetched' or 'conflicting' but it makes sense to me
Let's examine this a bit further...
-Assume we live in a free society where some commodity like gold or bitcoin has become the general money
-Assume I have lots of this money, and another guy wants some of it as capital to start his business... he wants a loan from me.
-I am willing to loan him the money at 10% interest per year until principle + interest is paid back
-He is willing to take that offer and agrees to the terms
Now... what part of that is immoral?? You call it "usury". By what right do you decide for either of us what is the "acceptable" price of money? Under what justification do you tell the man he may not borrow my money, or tell me I must refund the interest after the debt is paid?
Where is the harm? Your idea doesn't seem "far fetched"... it just seems "wrong." For if it's immoral to loan a man a money-commodity at a price, then it ought to be immoral to loan other commodities at a price... such as seeds or lumber or xbox games.
Why is it okay to loan a man one seed in return for two later, but it's not okay to loan him one dollar in return for two later?