"Seriously... Does anyone really think screwing a dog deserves a 20 yr sentence? As bizzare as it may be, does it even deserve a 2-1/2 yr sentence or a $5000 fine?"
Well, swap out 'dog' with 'child' or 'sister' and ask the same question.
What's your point? As with most issues where you could "swap out 'dog' with 'child' or 'sister' and ask the same question", the opposite answer results. Should it be legal to take your dog to the vet to be euthanized after it bit the baby? Yes. Should it be legal to take your 4 year old child to the doctor to be euthanized because he bit the baby? No.
That's exactly the point. Dogs aren't children (even your sister isn't a dog). Having sex with a dog is strange and should be illegal, but 20 years in prison seems a bit excessive. 20 years for raping a child is not excessive.