Randy Pizzolo was a drug-addled lowlife who robbed his mother's bank account to meet his shylock payments. This was what jaded veteran cops refer to as a "public service homicide." And you can believe that.
But this is a tricky defense strategy. If it works, you're telling defense counsel (and their clients) that it's okay to kill someone, as long as he was a career criminal and a scumbag. It's almost a vigilante defense. And I'll be honest, I think it sets a bad precedent. We can't be advocating vigilantism or vendetta defenses. It's a very slippery slope.
I'm hoping that cooler heads prevail and they allow Vinny a last minute plea that would exclude the death penalty. The guy will never see the light of day again as it is, so it would be a no-brainer for him. But I doubt that'll happen.