I believe a style is a title that someone gives to you. It is something that is earned. If a person is concerned about their "style", then they are all about ego and not about art or learning.
For most people, who are not genuises or child prodogies, I believe that you start out by copying everything you see. You see something you like, you discover how it is done, and then you copy it. You find all the great photographers and you copy the hell out their work, until you can come close to duplicating it. Then after a few years you keep the techniques that you like and discard the others. Eventually you unconsciously end up with a "style". Although this will probably change and evolve over time, but it will be you that changes it and you will no longer be copying.
I have seen beginners, when being critiqued, and when asked questions about their work will say "well that is my style." WRONG. Lack of technique and expertise is not a style. Incompetence is not a style.
The debatable point perhaps comes when an experienced person turns out the same looking work over and over again. Is this a style or are they caught in a rut.
I guess that I probably believe that when people are relatively inexperienced, they do not have a style. It is something that usually takes years to develop and hone and then someone else has to attach a name to it.