I don't think they're orthogonal; they're probably positively correlated.
What does orthogonal mean here? I know what it means in linear algebra, but I have trouble translating that into a colloquial sense.
Generally, the meaning of orthogonal in conversation has become orthogonal to the "real" meaning: It can mean both 'perpendicular' as well as 'parallel.' "At odds" and "unrelated." It's really kind of silly.
My interpretation of it reads: "Getting into YC and being successful in SV do not overlap." In other words, they are independent of each other...