> Demographics questions on job applications do not get shown to recruiters nor interviewers.

But Recruiters can glean this information from names and other information on resumes. And yes, many do deliberately try to use this information to decide who to interview. Recruiters at one of me previous employers linked to US census data on the gender distribution of names in their onboarding docs. They also created spreadsheets of ethnically affiliated fraternities/sororities and ethnic names.