Best I can tell, there is zero incentive for Quora (or any other site, for that matter) to care. Their current redirect logic in no way hurts their user experience.

Right now they protect their users' privacy. What benefit do they realize by providing their users' viewing history to other sites?

I personally think that the referer header was never a good idea. I disable it in my browser, and appreciate sites that do right by their users with privacy protecting default behaviors.