How naive.
You should see how the situation is in Islamic countries, for example:
The ban on loans with interest has very detrimental effects. For the one loaning the money.
If, for example, a person wants to buy a house, what essentially happens is that the BANK buys that house, and then sell it to the individual to a much higher price, to be paid off in segments.
Essentially, this is loaning necessarily coupled to mortgaging, so that the one loaning is effectively bound to live in that house for a considerable time (it isn't his to sell before he has paid down his loan!)
In pre-monetary societies, loans bred non-monetary interest forms like political obligations to be held, work duty etc.
In short, a simple monetary interest is the type of interest least damaging to the one loaning the money.
Furthermore, interest as such is perfectly justifiable in moral terms:
Since the one giving the loan yields control expenditure of his own money for a considerable time, it stands to reason and morality that he is entitled to be compensated for the loss of that control.
That compensation is effectively what interest represents.