There is no such thing as a Hispanic, ergo there is no “Hispanic community”. What is taken for a “Hispanic community” can be clusters of people of Mexican descent in the Southwest and Chicago, a large cluster of Afro-Caribbeans in the greater NYC area, Cubans of all races in Florida. Zimmerman has a Peruvian mother, so he doesn’t fit into any of those groups. There is a sizeable Peruvian population in Los Angeles, but I doubt that they were even aware of this trial.
These different clusters of Spanish speakers don’t eat the same food, listen to the same music, or, in the case of many of the Cubans, vote the same way. Hence the “silence” from the “Hispanic community”.
You make some good points, but I want to mention something.
Even for Blacks, it’s not generally the Black populace themselves making all the noise. In most instances it’s the agitators like Sharpton, Jackson, the NAACP, politicians and other loud mouthed advocacy groups speaking for Blacks.
In the Hispanic community there is more diversification, but that’s not going to stop La Raza, MALDEF, Mecha, politicians and other groups from fronting for them as if they were one people.