I get a vibe as well, though I don't share your theory of it. Older math/CS papers have a more conversational feel to them, and tend to assume that the reader shares a kind of philosophical disposition. Today, research papers often have a very corporate feel, and are bristling with "motivation". But I don't think it's at all difficult to write such papers without referencing race or gender. Many people do it every day, successfully. I'm curious why you think that race and gender have invaded math/CS.