I think that in any skill/talent/profession, it is tempting to identify the individuals that thrive at it -- seemingly without effort. Almost all "arts" have some variation of this myth -- programming, sports, painting, writing. Its easy to identify those people -- Pablo Picasso, Bo Jackson, John Carmak, Jane Austen -- and say that they were natural-born
whatever...
I reject the idea of innate "talent" or "skill". However, I firmly believe that certain individuals are more adept -- either through genetics or environmental factors -- at "learning" a skill, which is a by-product of the assumptions and abstractions that we construct to process information in the world.
I think that this myth is much more prevalent in the visual arts. Any one can be taught to draw; a good chunk of the first half of art college is unlearning the bad assumptions you have made about visually processing the world. Those that learn "quicker" are a product of an environment where they never made those assumptions in the first place. But that is simply the first step -- the foundation -- beyond that it takes hard work and practice... A dedication to the craft. If you lack the commitment to the craft then it will suffer... And I think that's true for anything: math, programming, writing, drawing, sports, cooking... and so on.
I think that telling someone they "can't" do something or they are naturally "bad" at it is definitely an environmental pressure that could affect ones ability to learn a craft. In fact, it doesn't sound like a good environment to learn anything.