Colleges which tend to be impressed by expensive extracurriculars or those associated with higher SES may be doing so as a deliberate policy. Doing so may produce an expected result of a frosh class that does not need that much financial aid, but allows the admission process to be nominally need-blind while allowing the available financial aid budget to offer good financial aid to those few admits from non-wealthy families.
A college that wants to tip the admissions class to include more lower SES students could easily adjust the criteria to favor extracurriculars that are associated with lower SES (e.g. working to help support the family, caring for other family members (young children, those with disabilities, seniors) while the parent(s) are working for pay) over those associated with higher SES students. Of course, it would need to have enough of a financial aid budget to do so effectively.