No--all IP developed is free to the world, so we wouldn't be able to use it defensively.

Apparently not.

  YCR is a non-profit.  Any IP developed will be made available freely to everyone. 

  We’re not doing this with the goal of helping YC’s startups succeed or 
  adding to our bottom line.

you could allow free use of patents under a license that requires the entity doing so to also allow free use of their patents. If you believed the patent system is largely counter productive (as I do), this would be an awesome way of trying to address this a constructive way.

what YC could get out of it ( besides making the world a better place ) is very good knowledge of the capabilities of potential entrepreneurs. Imagine one of these researchers then founding a startup. Funding that would be a lot less risky, so that's quite a bit of edge