People go to do their funky exercises wherever
(a) there is a free space, and
(2) there are mirrors
Power racks in mainstream gyms are usually free, and have mirrors next to them. Thus the curling, medicine ball pushups and so on.
The answer to this is to ensure that power racks are never free of people doing powerlifts in them. Competent people ought to be coaching others to squat, press, clean and so on. Failing that, smash the mirrors. You won't find people going to exercise in the one mirrorless corner of the gym.