Most people talking about their sports or instruments makes sense. 84% of applicants have parents with bachelors degrees, 80%ish of applicants identify as white or Asian, less than 1% of applicants were military or peace corps, less than 25% have had any significant work experience that would contribute to leadership or the like, only like 8% of applicants identify as LGBT.....
Literally the vast majority of applicants do not meet any of the criteria that one would consider 'typical' diversity. So they talk about something completely tangential, but it is of significance to them and they can talk about it. Everyone brings something new to the table, and you are 'lucky' enough to have something that is a traditional diversity marker that you can talk about.