Basically affirmative action in a nutshell. and if you are unfamiliar with that it basically means minority races/etc. (blacks, hispanics,native americans, etc. to name a few) are given a little preference for when they submit an application and there is usually an unsaid expectancy of having a few spots designated for them.
so whats the big deal? I, for example, am middle eastern and count as white (as far as i know) - so when i apply if they already accepted a huge chunk of white people and theyre comparing my app to someone URM - they will probably get the spot over me (if all else is exactly the same) and interviews are the same and all that