That argument cuts both ways, and you’ll have to admit that (while it may not apply here), the risk of futher violent acts on the part of someone charged with committing one is higher than the risk of someone charged with committing a violent felony being assaulted by a stranger.
And... no... the court has no liability in the event of an assault on Zimmerman.
But he hasn’t been convicted of a crime, just charged. When Zimmerman is exonerated how will he go about having his right to bear arms restored for a crime he never committed?