I'm confused about the responses to the OP because the responses seem to be focused on the park assist system. The OP's wording was clear, he specifically used the words "collision prevention ******** screams and slams on brakes", an action the parking assistant can't do. The system he is describing is the "rear park sense braking system", a detection system to prevent you from, for example, backing into a vehicle.
The collision avoidance displays a high-impact red warning display in the DIC accompanied by a loud warning sound and applies the brakes firmly, the same way as the frontal collision avoidance system does. I have not had an issue with this system while backing a trailer, one is a boat with surge brakes and the other is an 18-foot car hauler with electric brakes. I have had the system go off when backing down a steep driveway and approaching the roadway.
I'm assuming, albeit I have not tried it, the rear park sense braking system can be defeated and re-enabled at the next ignition cycle. If you have a PDF of your owner's manual search for "Rear ParkSense Braking Assist". They don't say much about it or discuss if it can be disabled. In my version of the owner's manual, page 234, the third item in the table is all I could find. I don't know if turning off the rear sensors using the center stack button will defeat the Rear ParkSense Braking Assist.