"Why does it appear that the vast majority of women prefer the same small group of men?" The chart doesn't show that. The chart shows that in surveys, women and men answer a survey with different average baselines for what "average" means. That's interesting, but it fundamentally tells you about how men and women answer surveys, not how they are attracted to the opposite gender. What tells you their actual attraction…
What is your conclusion about the graph, besides "interesting"? What is fundamentally different about how men and women answer surveys?