I don't recall Obama saying that if he had a son he'd look like Christopher Cervini. I don't recall people marching in the streets after Scott was acquitted. Hell, I don't recall this even making the news. I had to literally stumble across this:
And Snopes confirms it:
Complete parallel to the Zimmerman case with the exception that Scott shot Cervini as Cervini was allegedly running at him while Zimmerman shot Martin while Martin was pounding his head into cement. And yet, not a peep. Tells you something.