It wasn't Obama's place to speak on the trial in the first place. And it wouldn't be his place to get involved now to provide special federal protection. If the US Federal Government does not get involved that does not mean Zimmerman "is on his own" in the words of this questioner.
The premise of the question is part of the problem. People think the federal government is some magic fairy that should take care of all social problems and issues. It is not that.
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