Some people just require more practice than others. Study.
I think this is a really great observation, and inherent in the statement is this: we do not all have the same tools. Even if we had taken all of the same classes at exactly the same school, this does not change. And it is not simply a matter of "X person is not as disciplined as Y person". That is a gross oversimplification and ignores the idea that everyone thinks differently and that no matter what you say, there are biases in a standardized test.
It is OK to struggle with the MCAT. It is ok to fight with it for awhile. It is also ok to make your peace with it and realize, like I believe the second poster said, it is only one factor; you have good grades, went to a good school, and are (hopefully) smart and motivated. There are a lot of other ways to manipulate this process besides a stellar MCAT.
Why do people place so much emphasis on the MCAT? Well, besides being something that is easy to point to, it is the catchall for the douchebags. The people who won't ever interview well, don't have social skills, and NEED a good MCAT to get in.
Make peace with the fact that you need to take it and make friends with it. For me, the prep class was exactly that: it helped me become friends with the test. It made me appreciate how they were going to trick me and instead of looking for correct answers (of which there are only 25%), it taught me to look for common wrong ones. And after "moping" over the test for two years, I took it officially once and did well.
Don't let The Man (or SDN) get you down. You can do this.