The recognition of Non-Biological Entities and their unique abilities gave humanity the galaxy. Wrangling entities known as ghosts or spirits has its problems. There are those who view it as slavery or worse, slavery of deceased humanity. Spending your after life trapped in a jump drive doesn't sound so great. The possibility of a mass NBE uprising is often brought up. In fact such uprisings have happened on a local level many times.
Eventually someone realized, if NBEs could move a ship in or out of our universe using human technology to augment their power, similar technology could be used with human psionics.
Some cultures prefer enslaving the living to mucking about with specters.
The upside is that humans can be controlled and intimidated far easier than NBEs as visible, tangible, living beings.
The downside is that as living beings the technology is uncomfortable as hell at the best of times. It is painful and can cause psi burn out without proper precautions and it creates a market for slave rings. It also can create a psionic upper class controlling local space travel among other things and lead to oppression of non-psionics.
The Ghoul cults make extensive use of enslaved or brainwashed psionics to maintain their space fleets. The Empire uses the psionic tech when it's necessary. Some missions and cargos are too vital to allow around ghosts. These missions use psionics brought up within the Empire, living lives of privilege to buy their loyalty.Privilege usually means the safeguards are better hidden. The major's uniform the psionic wears so proudly may be programmed to strangle them on a certain signal. Their seven course meals may contain the antidote to a poison regularly injected into their bodies by an implant.
Despite these precautions, the so called Ordained Psionics are loathed by virtually all other psionics and liable to be attacked physically or mentally.
NBEs may freeze your blood or wreck your ship. They may have you jumping at shadows or have your shadow jump you. But given the treatment they receive from the living it's often what you'd expect. As much as we fear them and sometimes loath them one thing is certain, they do not enslave each other. That horror is entirely mankind's.