If it were truly fair then we would see an Avengers that is statistically probable sample of the population. Assuming they were mostly American then I would expect half to be female, 10% to be LGBT, 14% to be black, a similar percentage for other minorities, and that they were equitably distributed in terms of power, ability, morality, and mortality.
We dont have that clearly. We have a smattering of black heroes written by white men. We have arguably the most awesome and powerful hero being a tall, blond Aryan beacon of whiteness.
How fair is that really?