Not at all, these cases can't really be compared because the main difference has to do with the amount of evidence. People can't get convicted unless the jury is completely convinced that they committed the crime. Zimmerman and Casey weren't convicted because there wasn't sufficient evidence to prove without reasonable doubt that they did in fact commit the crime and that there couldn't have been a scenario where they could have been innocent. (There was no way to prove that Zimmerman initiated the fight, and there wasn't anything directly linking Casey to her daughters death). Vick got convicted because a dog fighting ring was found in his home, complete with over mistreated 70 dogs. There was more than enough evidence that he did in fact commit that crime. It's a bitch, but it just comes down to one simple thing: Are you okay with courts being able to convict anyone they think committed a crime, which would get people like Zimmerman and Casey convicted but also would result in innocent people being imprisoned? Or do you believe in innocent until proven guilty, possibly letting some criminals go for the security of knowing innocent people are unlikely to be punished for crimes they didn't commit?