Like any exercise people have to take into consideration personal injury history, individual fitness levels, age/possible bone degenerative disease concerns, and appropriate exercises to their individual needs. Just like I would never just blindly tell every training client to start squatting full depth with 300 lbs, exercises like Dislocates and Jefferson Curls must be performed with appropriate levels of resistance and range of motion for that individual, or even not performed until easier, less advanced/more appropriate for their individual needs regressions are proficient.
The normal human shoulder is designed to allow for the range of motion necessary to perform Dislocates, these muscles and connective tissues are also fully capable of strengthening, thus allowing weight to be utilized during the movement. That most people, especially adult men, cannot even perform unweighted Dislocates at even twice shoulders width, let alone shoulders width, simply proves my point about how unbalanced most people's training is and how horrible most adult's shoulder mobility is.
Again though, that doesn't mean I am telling everyone to grab an Olympic bar at shoulders width and do dislocates with it (though, that would most likely just result in an epic failure of basically no movement, but still not what I'm suggesting). What I am saying, just like if I were prescribing squats, is that people should gradually add range of motion with a light weight (something like 5 lbs) and then weight with the eventual long term goal of using an Olympic bar and an eventual shoulders width (or slightly outside shoulders width) grip.