We have all seen the kind of technology that humans have been capable of creating and it has been far from impressive. The creation of nanomachines is actually something that was contributed to by the order. It was given to humans in early stages of development to see how they can use them for the enhancement of humanity. We cannot allow them to get a fully functional nanite that controls all kinds of metal functions because we know they might use it as warfare.
So far the humans have proven to be unable to create a very powerful nanomachine that is able to control certain functions of the brain. The order have been able to use these nanites to control mental illness in humans, but this has been a very controlled and isolated experiment that is not meant to go public. Hopefully there will be a good enough system behind this and it will allow people to one day realize its potential for good.