Grades are Just Grades
No one should be defined by how they perform academically because, the truth is, academic performance does not sum up a person’s entirety. So you had an A on the math test, so what? It just means you are book smart and doesn’t imply the one who failed the test can’t do better at other things outside the classroom.
The world has gone beyond just what you learn in class because many of these things aren’t even applicable in the real world. Many factors can contribute to a person’s mediocre grades, and being unintelligent is not even one. It’s wrong to attribute ‘intelligence’ to how you perform in class because there are many other ways to measure being smart.