In all racing I know of and am familiar with, whether 2 or 4 wheels, it is the sole responsibility of the overtaking rider to take appropriate action to avoind a collision.
Yates, in my viewing of the race footage, (multiple times (thanks TIVO)) it seems fairly clear (to me) that Yates violated this rule. (By the way I think Yates is a great racer.)
The action that Yates took after the collison only seems to verify that he was angry - but he should have been angry at himself for his miscue, NOT Fania. Not once but twice did Yates assault Fania (I am a former prosecutor and have seen lots of similar anger driven actions end up in criminal court)
The penalty is relatively light. I think a more appropriate action would have been to suspend Yates from one meet and put him on probation for 5 additional meets. Make him think about consequences before he acts.
Paul Tracy in CART (or whatever it is called these days) Juan Montoya in F1 and Michael Andretti have all been put on probation for rought driving, the problem was cured.
Ask yourself; "What do you think the result would have been had Fania done the same acts to Yates?" Think about it.
Thanks for reading.
Rick in Portland Oregon