I'm neither surprised nor disappointed at their lack of public displays of warm fuzzies.
From Hamilton's point of view, Rosberg has punted him twice and blamed Hamilton in both cases. Just where was Rosberg expecting Hamilton to go?
Barcelona:

Austria:
Regardless of your occupation, if someone had taken measures to ensure you fail at your job, I cannot imagine wanting to give them any attention.
From Rosberg's point of view, in each of the last two years he has had a huge advantage in points as a result of his good driving and tactics along with lots of mechanical and tactics issues from Hamilton. Last year Hamilton came back and won the Championship. Kinda looks like the same thing might happen again this year. For someone with a pretty health ego (as all F1 drivers are going to possess) it cannot be easy to see someone in identical kit consistently beat you.