If your neighbor lent you a hundred bucks and you loan ninety bucks of it to a different neighbor, you've done the same sort of thing. Of course, if you do it at a small scale, you're at high risk of having empty pockets if that neighbor wants their hundred back at an unexpected time. But do it to a thousand neighbors on either side of the exchange, and you can probably get away with re-lending most of it for a long time.
They aren't granted special money-making abilities; more the reverse: they are under regulations to prevent this power - which is, in happy times, very good for the economy - from being abused. We can argue about if those regulations are strong enough or not, but I think the "money is bullshit cause banks print it out of thin air" arguments are intentionally misleading from opponents of a system that otherwise isn't actually terribly complicated.
I disagree that it is intrinsically wrong that some people can do something that you cannot do.