Sex is the center of existence and it is a pity that people refuse to accept this because of Christian values. Sex is what creates life and gives it meaning. The fact that this makes you uncomfortable is a pity.
While i understand why you have this view about natural talent, I believe that everyone is born with the same capabilities barring some form of disease. Aside from that, how good a person is at singing is a factor of two things. 1st is how much positive reinforcement they receive for their efforts in the arts, be that painting or singing. The 2nd is acceptance that we are animals and what singing is, is an expression of a primal desire. People who are nervous at singing are so because they loathe to reveal to others that they are, factually, animals. They learned that to be an animal is to be a bad human, but we are all animals that came from sex and continue on because of sex. Yes, not everything in life or every song is about sexuality. But downplaying its importance is precisely the barrier between singers who have stage fright and someone like, I'll mention again, Shakira.
Sexual enlightenment leads to better singing. Christian fear leads to sucking.
Also, yeah so there are ways to sing that permanently damage the voice. So what? Screaming does that. You can go ahead and tell someone that screaming is a bad kind of singing because it damages the voice, but that's ridiculous. The human body grows strong to what pressures reoccur in its systems.
Prince was told that his way of singing was wrong. Now those people eat shit while Prince, actually dead, lives in forever singing the way that worked for him, and haters died mad.
Look, I get it. Most cultures deeply fear sexuality. That is exactly why I am saying that this fear is the real vocal killer. If you are asexual this is no excuse because (healthy) asexual people still masturbate. Let me put it this way: If you would feel embarrassed to think of your singing as analagous to sexual pleasure, then that embarrassment is your limit.
My ted talk... part two.