Rotties are not "savage" dogs. If raised right they are absolutely lovely animals.
Yes, the owner should be in jail for letting his dog run free and for the damage the dog caused. Plus he should owe the family a large financial settlement and pay for all medical bills.
Also, some responsibility goes to the family of the child. If there are stray dogs around it's their responsibility to protect their child.
Dogs don't attack unless they're provoked. Something the child did made the dog feel uncomfortable and caused it to attack. So the parents should make sure that the child is secure when out of the house. 2 year olds should also not be "running free".
We have 6, count em, 6 dogs and they stay in our yard or when they are out on walks they are on a leash. This is a concept Thai people don't seem to get. We have a neighbor who lets their dog run free. Lovely animal who we've known since he was a pup, but when he's walking around it makes our dogs nuts and causes a lot of noise.
Many Thai people want dogs, but don't know how to care for them.