The Dean of Admissions at Mount Sinai told us in a webinar in the application season that all applications are pooled together and "ranked" based on everything (LOR, CV, publications, academic record, research experience, etc) and they set a cut off value based on how many interview invitations they want/can send and they didnt discriminate by country, sex, gender, background or anything. But, seeing the results page 90% of accepted students are american in most universities and institutes, so they accept more US applicants than international applicants so I dont think thats necessarily true. I have no problem in giving preference to students from their own country, but they should specify it in the admissions requirements so we know the probability of being accepted is lower, even if we have better cv than US applicants.