I also think newer or untrained people sometimes move along the wrong ukemi path because they are trying to escape pain, but either don't know how or, in some cases, simply can't move in the way that minimizes pain (yet).
Not to disparage anything you're saying, but (and this is really addressed to the conversation as a whole) isn't this fairly obvious? Ukemi is a learned skill, it's not something everybody does automatically. Why would we expect J. Random Person to go with the technique? They don't know how.