...because photography depends so Mach of a machine that does the picture, it is in its essence a different kind of art form than painting for example (and to what it is constantly compared)...
And yet most other forms of 'art' involve tools of some sort - which can easily be beyond the artists technical ability to create, or in some cases even perform routine maintenance on (particularly musical instruments, where specialists are required to tune pianos, etc).
I think it is as you suggest, the direct comparison to painting, where a camera CAN be used to create an image with little apparent skill on the part of the photographer. For those who have not spent time trying to create something more, it is difficult to imagine the level of skill required to do so, or the time and study required to attain that skill.
With a painting, most who are nor proficient are aware they 'cannot paint' (I fall into this category) - with photography, many just think it's luck (or an expensive camera) that makes the difference.
As competition between the manufacturers increases, more and more people are able to afford a camera that allows them the controlls to move away from 'auto' and to explore the creative possibilities - in time, perhaps, this will lead to a greater appreciation of the skill in consistently
taking 'great' photographs requires.