People here (and probably elsewhere, like in high schools, etc.) generally tend to overvalue quantifiable aspects of an applicant (e.g. SAT / ACT scores, GPA, rank, race / ethnicity, legacy) over those aspects which are subjectively scored and not visible on these forums (e.g. essays, recommendations) when assessing admission chances, even though the latter may be highly important for admissions at highly selective colleges.
So it is no surprise that race / ethnicity is seen as a very important factor in college admission, regardless of whether it actually is at the particular college.