Having seen the video, it looks more and more like a racing incident. Rosberg is simply following a line he's decided upon on corner exit, while Hamilton dives into a closing gap.
One telling part here is that Hamilton is on the outside of Rosberg mid-corner and on exit. On exit, Rosberg puts his car in the middle of the track to cover his options, and Hamilton cuts across his rear going for a gap that's closing.
From 2:13 in that video from Sky, however, you can see that everything is over within a fraction of a second... after Hamilton had committed to that move, neither driver really had the time to avoid the incident.