Sigh. I see a lot of these rationales. Essentially, it goes like this.
What Michael Vick did really sucked.
But everything humans do to animals really sucks anyway.
So, let's cut him some slack and forgive the guy.
In that case, why do we punish humans for crimes against other humans? We are a pretty cruel society that cares little for children, the poor and the elderly. If someone harms them, well, it's okay if you place it in context.
Let's give the perpetrator a second chance!