Because you're weighing in on a complicated subject without considering your inherent biases. You're conflating the success of individuals with equal opportunity. Having a black president doesn't mean we're in a post-racial society, being able to point to black athletes and movie stars doesn't mean there's no disaprites in educational funding or discrimination in employment.
But worst of all, you've decided that because your advantages of birth are invisble to you, they must not exist. This is like deciding you don't have a cornea because you can't see it directly.
Look in a mirror, and instead of dismissing the idea of privilige, see if you can actually see it in your life experience. Perhaps you can look here as a starting point. https://www.uakron.edu/dotAsset/1662103.pdf