Just a Rant; Feeling Mad

Jesus Christ. An intern is not a clinician. An intern is not a supervisor. Throwing a self-righteous hissy fit is not the same thing as acting appropriately for a client.
When the previous clinician worked here, their intern was asked to leave the internship/practicum early after they cussed out an employee (happened before I worked here).
Management agreed to take on a different intern from that same school and have me supervise this intern months ago without any real support with being a new supervisor. The intern went against everything I instructed as far as transferring a client (complete with a self-righteous lecture about how they always do it this way in the area where intern normally works, which is completely different from the area they are interning in) and completed the program, leaving a mess that I have to clean up. When I bring some of this up with management, I may get sympathy, but nothing actually changes. What does this school have on my workplace? Why is preserving the relationship with this school important enough to continue to agree to take on interns who clearly are there to lecture, not learn?