A theme park has inspectors who test every ride on a regular basis to ensure that the riders are safe - although every now and then it runs off the rails, so to speak. But it is extremely rare, on the percentage of successful rides against injuries, that anybody gets hurt.
If you wanna do a tandem meat-bombing run, you have to sign their forms of "all care but no responsibility", listen to their training, watch a video, get strapped into a harness by a professional, and you know that you are taking a big risk to do so.
These carnival rides have no such checks, have no training or warnings, little supervision on entry or exit, and a low-time pilot who wants to show off. Big difference.