Instinct is fine, but it should be awarded a red card. Taking the law into your own hands is not something we want to see on the pitch, just like the biting, just to be clear.
He wasn't taking the law into his own hands. He reacted out of self defense, literally while being assaulted. You can't punish a guy for defending himself from an attack on the pitch. It would be one thing if he were bitten, got up, walked over to Suarez and hit him in the face...this was just a pure defensive reaction that was completely justified.