There are many life forms on Mars that humans are not able to see because they are able to hide themselves with superior technology. Some of the species that live on Mars are actually interested in taking over planet Earth, but the order have been able to keep them at bay for a long time now. The order does indeed trust the most superior alien race on Mars, but there are other inferiors species that are dangerous to humans and superior to human technology that might pose a threat to human kind and they are not trustworthy.
The order will always monitor the intentions of this species and trust the superior race of alien that inhabit Mars to make sure that the species that are dangerous to humans are kept away from Earth. Hopefully they will look for another planet to conquer, but Earth is very convenient to them even though they would need to make a few changes to make it their home.