"What I am hearing you say, is that this therapy did not work for you, or you cannot imagine it working for you?"
No. That is not at all what I am saying. Rage and healing have no business being in the same sentence and to call something 'rage therapy' is an oxymoron. I have done years of my own experiential therapy and also practiced this with clients, including all sorts of anger releases, bioenergetics, body-centered therapy, primal screaming, rebirthing, re-parenting, etc, etc, etc... you name it! While these practices tap off and discharge the immediate energy of the emotion, it most definitely does NOT lead to healing. That sort of anger is a bottomless pit, and the fact that you are still beating cushions with a tire thumper precisely illustrates my point. If this was truly a healing therapy, such aggressive action would no longer be necessary.
Anger is a legitimate emotion, however, it can also very easily become what is called a racquet emotion. Because it often gives a person a false sense of power, they revert to it rather than addressing the underlying emotions that are at the root... usually of fear and sadness. The problem is as long as the focus is on the anger there is a denial of these more vulnerable feelings, and so the anger cycle keeps continuing because the the fear and sadness are never healed and the person continues to feel the need to hide their vulnerability.
You have also made some very interesting comments about emotions, which may shed a light on part of the problem. You said... "It is more difficult for me to uncover the ugliness of my emotions...". Why are you judging your emotions as ugliness? And to which one's are you referring?
And because others also read these posts and since I am aware of some of the dangers of these types of therapies (including physical injuries)... I am also including a video that discusses rage therapy...