I find what you say about the Ivy League very interesting. My only connection to those schools comes from the film and tv series “The Paper Chase.” What I remember SO vividly in the movie was how incredibly hard those kids worked. It was very impressive. Now either times have changed or the movie was exaggerating. Probably the former.
Ivy league schools are completely political. Left wing political. A 'C' is so easy to get in the non-science classes, that it is a defacto pass. To get an 'A' takes work and effort, some try, some don't, most pass. If you are a minority and try just little, you get an 'A'.
The sciences are difficult, and probably require effort to get a 'C'. Most people in the sciences are hard workers so 'C' grades are rare.