Zombie threat assessment

Probably because one scratch/bite could make you a zombie too...

Ralph Wiggum

Chances are if him biting you will make you a zombie than more than likely you biting him will make you a zombie as well

According to the lore, zombies don't have fear or any concept of pain, so they put all of their strength into the fact whereas most of us are afraid to get hurt. Our preservation instinct is a disadvantage here.

You just ate a decomposing body. Enjoy the host of new bacteria you just introduced to your meat suit.