I agree. I'm very pragmatic, and am impressed more by results than by theories. Because of that, I do believe that TP exists. Many people have benefitted from the programs that have been developed by Joel Turner and others to treat target panic as a condition caused by the subconscious mind taking over the shot, which can only be treated by taking control away from the subconscious mind by using an external trigger. However, an unusual number of people have not benefited from those programs, and I don't believe it was for lack of trying, in most cases.
The most usual symptom of target panic is not being able to hold the arrow at full draw until the shooter is ready to shoot. I think this symptom can occur for a variety of reasons other than the subconscious mind taking control of the shot. I am a good example of that. My “subconscious” release was working fine (I put subconscious in quotes because I don't know if my release is subconscious or not; I just hold until the shot goes off). External releases work fine too. For me, switching to an external release was about as effective as trying to repair a broken clutch by working on the transmission.
In my case, what helped was treating the problem as a distraction, and finding out what that distraction was. Distractions are treated by learning to increase concentration to eliminate them. I discovered that my distraction was anticipation of the shot, an emotion. Once I had identified what the distraction was, I could recognize it when it occurred, and eliminate it through concentration. This oversimplifies how I solved the problem, but the point is that it worked, and it didn't involve switching to an external release.