Whether the origin of social justice in universities comes from students or the faculty is irrelative. Fact is that elite universities in the US stand strongly for social justice, and expressing those values in your essay and interview does increase your chances of admission - especially in comparison to expressing contrary values. Thus, if your only goal is to get in, you are better off emulating the values the university has chosen for itself, regardless of your actual personal beliefs.
Only if they really “stand strongly” and give higher scores to such views and it's not just marketing. If they advertise about social justice, but the admission process is in fact pretty conservatives, this posture will not have a dramatic effect.
But anyway, even if this is true, that doesn't mean that it's the current Elite's views, just likely to be the future Elite's views (assuming that higher education pays a significantly higher role than the set of other Elite's beliefs they'll encounter later in their lives and that they'll mimic too in order to be successful later, since the process you're describing occurs over and over and over in someone's life).
I think the only thing where we differ is that I consider elite university faculty (and the institution as a whole) to be part of the elite and you don't. I'm not saying either is correct, it's just where you draw the line.
There's a difference between “being part of the elite” and “being representative of the Elite as a whole”. I'm not arguing that university members aren't part of the Elite, but I'd argue that they are a narrow part of a much broader Elite and they are commonly more progressive than the rest of the Elite.
